Reader question: Use old iMac as an external monitor

Rudolf from Switzerland asked me if he could use his 10 year old iMac as a monitor for one Mac mini 2018 he intends to buy. Since this question is also interesting for other Apple users, I have prepared the relevant information as a contribution. Because not only the Mac mini, but also the MacBook Pro / Air can theoretically be coupled with the iMac via screen synchronization for extended display. How to do this and what requirements must be met, you will read in the following.

An iMac as an external monitor for Mac, Mac mini, MacBook and Co.? That is possible - but there are some requirements. You can find the instructions here! (Images: Apple)
An iMac as an external monitor for Mac, Mac mini, MacBook and Co.? That is possible - but there are some requirements. You can find the instructions here! (Images: Apple)

Using the iMac as a monitor - requirements

There are certain prerequisites and system requirements that must be met so that the iMac can be used as an (external) monitor on a Mac, Mac mini or MacBook. In the following list I have put together the compatible models for you. Because not every Apple iMac is made for screen synchronization mode:

  • iMac end of 2009 27 "
  • iMac mid 2010 27 "
  • iMac mid-2011 to mid-2014

iMacs from the end of 2014 with 27 “and 5K retina displays cannot be used. In addition, it must be ensured that the above models have Mac OS X 10.6.1 or a newer version of macOS, but may have a maximum of macOS High Sierra. The more recent macOS versions (Mojave, Catalina, Big Sur) no longer support the target display mode. You also need a keyboard that plugs into the iMac - the original model is best.

If your devices and operating systems do not belong to those mentioned above or if setting up the Display Target Mode is too complicated for you, continue here: Use old iMac as a monitor via USB (without official compatibility). This is how you can get a high-resolution second display more easily and without having to buy a new monitor!

Old Apple iMac as a screen extension - cable

So now you already know which Apple computers are required with which operating system and which peripherals. But of course the image source, i.e. the new computer, and the model that is stored as a display have to be connected. The connection can be established using Mini DisplayPort cables and Thunderbolt cables as well as a combination of the two. Here is an overview:

iMac that is used as a monitor Cable for the monitor function Connection to the other Apple computer
iMac (27 ″, late 2009) Mini DisplayPort to Mini DisplayPort
(on Amazon)
Mini DisplayPort or Thunderbolt
(on Amazon: MiniDP / TB3)
iMac (27 ″, mid 2010) Mini DisplayPort to Mini DisplayPort
(on Amazon)
Mini DisplayPort or Thunderbolt
(on Amazon: MiniDP / TB3)
iMac (mid 2011 to mid 2014) Thunderbolt
(on Amazon)
Thunderbolt
(on Amazon)

Source: Apple Support Document HT204592

The old iMacs usually have the mini display port (left in the photo), while the new Mac models have USB-C ports (right). The two options listed below should provide the right connection here (Photo: Sir Apfelot).
The old iMacs usually have the Mini-Displayport / Mini-DP (left in the photo), while the new Mac models are equipped with USB-C ports (right). The two options listed below should provide the right connection here (Photo: Sir Apfelot).

Update 12.12.2020/XNUMX/XNUMX: Mini-DP to USB-C solution

If your Macs have the sockets shown above, then I have a combination of cable and adapter for you that works with a high degree of security. A reader (thank you, Robert!) Wrote to me that he is using an old iMac late 2009 on the Mac Mini 2018:

From the two products you put together an adapter cable that should also do its job for you. You may not have to read any further in the article, because there are other solutions below that did not work for all readers. But I still want to leave it in here as a backup.

Warning: some USB-C to DisplayPort cables do not work

As a reader recently wrote to me, the connection between iMac and MacBook Pro is not working. He used a cable that fits into the iMac (DisplayPort) and the MacBook Pro (USB-C), but it still doesn't work.

At first I thought it was because the cable is not a Thunderbolt 3 cable, but it seems that there are also USB-C to DisplayPort cables that do their job. So there is still a little trial and error. I've listed both variants here. Once the solution with the Apple Thunderbolt cable and adapter and once a USB-C to mini Displayport cable, which according to a reader (see comments below) works for him where the Apple solution has failed:

1st option: Thunderbolt adapter and Thunderbolt 2 cable

2nd option: USB-C to mini DisplayPort cable

I would recommend ordering both and then keeping the solution that works. The other cables or adapters can then be sent back to Amazon.

Activate screen synchronization mode - Here's how

If you have both Apple computers connected with the correct cable, both are connected to a power source and switched on, and the old iMac has a keyboard, then you can start. Just follow these steps and nothing should stand in the way of using the old computer as a monitor:

  1. Connect both computers together and turn them on
  2. Leave iMac on the login screen
  3. Log into a macOS account on the other computer
  4. Press cmd + F2 on the iMac
  5. If that doesn't work: press cmd + Fn + F2

Also interesting: “Keyboard shortcuts for the Mac” book tip

Troubleshooting - If it doesn't work right away

Points 4 and 5 are listed as alternatives, as the menu item “Use the F1, F2 etc. keys as standard function keys” could be activated in the system settings of the secondary device. So if the combination of Command and F2 doesn't work, just try the alternative. In addition, this shortcut has to be pressed on the keyboard that is connected to the secondary computer - pressing it on the Mac mini, MacBook or other connected computer does nothing. In addition, the problem could be with an Apple or third-party keyboard that is too old. It is best to use the keyboard that came with the iMac.

It is also essential that the secondary computer is in the macOS login window. No user account must be open or any version of Windows running through Boot Camp. In addition, the primary Mac must be logged into a user account. If that still doesn't work, it can help to connect a “real” external monitor first and then try the iMac again. Using older iMacs as monitors is generally a better idea, because the color fidelity and sharpness of the displays (even if they are not yet 5K Retina displays) have already been impressive.

Update 18.03.2021/XNUMX/XNUMX: Use iMac as a PC display?

Yes, that should work too. In the comments below, I sometimes made different claims because I didn't know any better at the time, but it is correct: You can also use an iMac as a monitor for a Windows laptop or desktop computer. The prerequisites and the procedure are as described above.

Answer to Rudolf's question - Yes, it should work!

If the old iMac is one of the above models and connect it to a Thunderbolt 3 (USB-C) to Mini DisplayPort cable is used, the new Mac mini 2018 should be able to successfully transmit video and audio signals. By the way: The linked cable should be perfect for this; a customer review (in English, but at least detailed) says the following:

I am really excited about this because it was very difficult to find the right cable. I have just received the cable USB C to Mini DisplayPort to connect my Mac Book Pro 2017 with touch bar with my iMac (middle 2010) to use it as a monitor. It works perfect !!! It saved me from buying a new Monitor or a new iMac.

Apple iMac as a monitor - questions and answers on the subject

Don't you want to buy an extra screen for your new Mac, Mac mini, MacBook or another iMac because you still have an old complete computer? Cupertino standing there, I hope this post was able to help you. Thunderbolt 3, Thunderbolt 2 and Mini DisplayPort allow you to connect quickly and use the screen synchronization mode. If you have any questions, tips or tricks on this or related topics, please leave a comment!

Did you like the article and did the instructions on the blog help you? Then I would be happy if you the blog via a Steady Membership would support.

408 Responses to “Reader question: Use old iMac as an external monitor”

  1. Interesting topic - that's exactly how I do it: a Mac mini 2018 on an iMac 27 ″ late 2009. It works - almost - without any problems.
    It's actually just inconveniences that have to do with the brightness control in particular: when switching to the mini, the brightness on the iMac is always at its maximum, so my eyesight cells are almost blown out. Then you have to regulate the brightness down using the function keys on the iMac keyboard. There is no onscreen feedback. When switching back to the iMac, the brightness is then minimal, then I have to turn it up again.
    Well, inconvenient, but I'm happy that my iMac does this job well, because it can no longer Mojave (but remains my workstation, the mini with Mojave is only developed).
    Oh yes, one more annoyance: if the mini wakes up from sleep without motivation, the iMac screen switches automatically.

    1. Hello Robert! Thanks for the info. These are of course small losses in terms of comfort ... I think you have to put up with that when you use such an old iMac as a display. : D But I honestly didn't know that there were the restrictions. So I'm glad you mentioned them here!

      1. Hello Robert: can I also use an iMac 21.5 ″ as a monitor for a mac Mini M1 2020? the iMac is already very slow, the M1 fast?

      2. Hi Jens,
        Thank you very much for the great tip, I am also very enthusiastic about your tip, with the Ruipoo cable it worked immediately. If I leave my iMac in login mode or boot it up normally and then plug in the cable, it immediately becomes a screen for the mini - without any keyboard shortcuts. That’s great. My question is: If the mentioned key combinations don't work to toggle back and forth - is there another one? I always have to pull the cable to get back to the iMac. Is it also one of the restrictions that one has to accept? My iMac is from mid-2010, 27 ″. The Mini of 2020 (bought last week).

        Many greetings and 1000 thanks! Bea

        1. Hello Bea! It's nice that it works for you right away. Because of the keyboard shortcut: Command-F2 is the only one out there. If that doesn't work, I don't know of any other. :-(

          1. Hello, I connected 2 Imacs (mid 2010) to a mac mini (2023) M2 chip and installed the "virtualkvm" program on the Imacs or in the login programs. Then just start the Imacs and when they are booted up the mini and it will connect automatically. You don't have to do anything anymore. When you shut down the Mini it becomes the Imac again. Greetings

          2. Hello Benni! Thanks for your tip. I didn't know virtualkvm at all. Seems like an interesting solution though! And you connected both iMacs at the same time and both work with the new Mac Mini M2??? According to Apple, that shouldn't be possible... at least that's what they tell the people in the shops who ask if the Target Display Mode works with new Macs. Then I know in advance that it is possible and even with the M2!

        2. Hallo,
          I would like to connect my Windows PC (Mini-DP port) to my iMac 2013 (Thunderbolt port). Is there a cable for this, possibly with an adapter?

          1. Hello Dominik! The Mini-Displayport and Thunderbolt 2/3 connectors are the same. That means you only need to use a mini-DP cable. I've been using those from CableMatters (Amazon link) had good experiences, but that is of course a matter of taste. I hope I'm not wrong and your iMac doesn't have an old Thunderbolt 1 port. If so, please report back!

          2. The 2013 iMac only has one Thunderbolt port. And the Windows PC only one HDMI or the round mini DP.

          3. Yes, I am aware of that. But the question is, is it a Thunderbolt 1 connector (looks like a rectangle with one side tapered) or is it TB 2/3 (looks almost like a square). There is no such thing as a round Mini-DP. Maybe it's different on the PC?

          4. I've already tried that. Unfortunately, that doesn't work because there is no Thunderbolt cable. Also, here the mac is used as the source and not as the monitor.

          5. Hello Dominik! It doesn't have to be a Thunderbolt cable. I know this because another reader connected his Mac to an old iMac with such a cable and it works for him too. Must be something else.

          6. Hallo,
            i would like to connect a windows laptop (hdmi) to an imac to use it as a display. Which cables/adapters do I need for this?
            Lovely wishes

    2. Hans Peter Achatzi

      Hello, today I found out from apple support in a chat that a current MacMini (2022) cannot be connected to a 27″ iMac late 2012 as a monitor. I find that very annoying – and not ecologically (and economically) sensible.
      Can you tell me otherwise?
      That would be great!
      Thank you - and peace and health to all of you!

      1. Yes, that's right, I have a usb-c connection and the imac has a Mini DisplayPort. How does it work with Luna? Thank you very much and best regards

        1. This is via WiFi. You get a small dongle that goes into the laptop. Then you install the Luna Display software on both devices and the two connect. Works surprisingly well. Tried it out here on my wife's old iMac 5K. While the 5K isn't supported, I believe it's 4K if you have an MBP M1 on the other end. However, I don't know what is sent on your laptop.

          1. Hello, does this mean that the 5k Retina can then be connected to a MacBook and used as a monitor? I have an iMac 5k from 2016 and would like to use the screen. It would be great if that were possible. So far I've only ever come across "it doesn't work".
            Regards
            Christian

          2. Hello Christian! Yes, “it doesn’t work” applies to Apple’s on-board resources. My wife also has the 5K iMac and connects it to “Luna Display” with her MacBook Pro. This works well and also offers more resolution than the Apple solution, which doesn't work anyway.

    1. Hello Heinz! Unfortunately only the 27 inch iMacs have the "Target Display Mode". Without it, using it as a second monitor won't work. :(

      1. Hello! I use my iMac (20 inches, mid-2007) as a display for my MacBook Air (2018) via Airserver (airserver.com, approx. 17 euros, trial version for 2 weeks). The program is installed on the iMac and controlled by the MacBook via AirPlay. There are, of course, restrictions on the resolution. At least Mac OS X 10.9 is required.

          1. Hello Klaus-Jürgen! Sorry for the late reply. Yes, there is software from LunaDisplay that you have to install for one Mac and the other. LG!

      2. Hello, I have an iMac 27″ from December 2011 and want to connect it to a PC as a second monitor with Thunderbolt/HDMI as described. Unfortunately, that doesn't work with the two specified key combinations. The iMac is not recognized as a display and always boots normally. what am I doing wrong here ?
        Thank you in advance for your help.

        1. I think it's correct that he's booting up. You only have to press the key combination when you are logged in. Please read the instructions above again.

  2. Wolfgang Stanic

    Hallo,

    I can't find a cable anywhere, Thunderbold on sisplayport.
    Can you tell me where I can get it, right? i think wrong.
    Thanks for an info

    1. Hello Wolfgang! It would be important to know which Thunderbolt version (1,2, 3 or XNUMX) and which display port (mini-DP or normal size). Can you maybe add that? Thank you!

      1. Hello Robert! Thank you for your help. I once linked the two things so that you can find them faster. For the cable, I took that from CableMatters. They have pretty reliable cables.

  3. Hello!

    A very interesting article. I am facing a situation similar to what you can read in the comments here. My iMac 27 “(2011) has reached the end of the macOS flagpole. I would like to continue to use this iMac in its current state, but also have the latest macOS available. I'm considering getting a Mac mini and using the iMac as a display. This seems like a viable option.

    However, I would like to be able to use the iMac's keyboard and mouse to work with the Mac mini after switching to display mode.

    Unfortunately, I was unable to find an answer to this question during my research. - So this can work this way, or do I have to use a keyboard / mouse attached to the Mac mini.

    Thanks in advance for an answer.

    Chris

    1. Hello Chris! So basically you can of course pair the iMac keyboard and mouse with a Mac Mini, but not at the same time. That means they will only work as an input source for the Mac Mini. If you are looking for something that you can use with both Macs at the same time, then I would give you the Satechi Slim Wireless Keyboard recommend. You can pair these with several Bluetooth devices and then switch back and forth between them at the touch of a button.

      Logitech also offers a keyboard and mouse set that can be paired with up to three devices: Logitech K375s and M720. This could also be something for you if you want to operate both Macs at the same time. I hope this answers your question and I didn't get you completely wrong. : D

      1. Hello Sir Apfelot,

        Thank you for your answer. You got me right I just want to use the processing power of the Mac mini and keep the existing peripherals as they are. If that works, I am satisfied and would want to use this solution. - However, an optimal solution would have been if the “external” Mac could have been opened via a window and switched back and forth similar to “Parallels”. Unfortunately, you can't have everything ...

        Now I have read on other websites that you have to be logged in with an account on the external Mac in order to establish the coupling. This complete establishment of the connection is not entirely clear to me. Is there already a thread on this?

        According to my current understanding, it is not possible to switch back and forth between the two computers, because if you disconnect the connection, according to other comments, the computer that fulfills the screen function should remain dark. So keyboards and mice that can be switched over would not be a remedy. But maybe I didn't understand everything either.

        The subject is complex and if you want to explore everything before investing in hardware, it is difficult. You can't test anything.

        Alternatively, I could get a new iMac. In terms of price, you get to comparable regions. You just have to have the space on your desk to be able to place both devices.

        Conclusion: As a decision-making aid, it would be helpful for me to know how the startup procedure of the two computers has to work.

        A completely different approach would be to connect the external computer via VNC. But here, too, I am faced with the problem of how to start this configuration without having first started the system with the keyboard and mouse on the external computer.

        Regards
        Chris

        1. Hello Chris! You started several questions in your comment. I'll try to do it one by one:

          1. Switching back and forth between the iMac and the Mac Mini does not work when the iMac is in target display mode. To do this, you would have to reboot it, which is very cumbersome.

          2. Personally, I would choose the variant and get a new iMac, because the old iMacs do not have a retina screen, which of course makes the display much worse. I haven't quite understood why you would have to have both iMacs running in parallel. What can the old iMac do that the new one can't ???

          3. A guide for pairing? You have just landed on the relevant article you are commenting on. : D

          4. The solution via VNC is possible. I would then set the iMac so that it boots without login and starts VNC directly when the system starts. Then you can access it directly from the other Mac even after restarting and you don't need a keyboard and mouse on the iMac to log in. The configuration is very simple ...

          I hope I have answered your questions!

          Greetings!

          Jens

    2. Hey Chris,
      I also hoped to get by with just one keyboard, so I tried a software solution (unfortunately I can't remember the name of that).
      However, all attempts did not work. When the iMac is in Target Display mode, the keyboard sharing software can't handle it. This keyboard only works as a brightness regulator and as a toggle switch.
      I made use of a second keyboard and mouse that were lying around in my pool.

      What also works (for smaller uses): Use screen sharing. This also allows you to do copy / paste between the systems

  4. Maybe I hear a misunderstanding from Jens, so I'll describe my use of this combination of iMac late 2009 and mini 2018 again.

    You are completely logged in on both computers, otherwise there is no other way. It's not like Firewire Target mode, where the Mac is just a hard drive.

    I log into the iMac as normal. Then I switch the mini on using the power button, the iMac screen switches automatically, but the target display mode must have been used beforehand. I can't say exactly how it works the first time, but you always have to be logged in to the iMac first.
    Auto-login is active on my mini, but it doesn't have to be, you can also go through the login screen.

    In daily operation I use it like this:
    - The mini and iMac sleep, I wake up the iMac with the keyboard connected, normal work is possible.
    - Now I wake up the mini (e.g. via its power switch). The screen switches to the mini, with full brightness.
    – The keyboard and mouse on the iMac are "switched off", only the brightness keys (possibly together with Fn) and above all the Shift combination still work (Command-Fn-F2).
    - There is no sound on the mini through the iMac speakers.
    - I use the mini with a second keyboard and mouse, both via Bluetooth.

    You can only return to the iMac using the keyboard on the iMac.

    What else works: on the iMac (account) I start screen sharing for the mini, on which I previously shared it in the “Shares” area. Now I can operate the mini completely with the iMac keyboard and mouse, of course with a certain loss of display speed. This even works full screen, for example on a separate “desk”. (Sorry, sometimes the terms might not be right, I run a lot of programs in English, because of developers and such ;-) ).

    You can also go to the iMac via screen sharing on the mini, it becomes almost pathological when the screen sharing is running again -> recursive chaos ;-)

    As far as my maybe a bit dingy explanation, please ask again.

  5. Addendum: you can still play sound from the mini via the iMac speakers, but not from both “accounts” at the same time. In the "Sound" settings on the mini there is a "Color LCD" output device of the "DisplayPort" type that you can switch to. Or you can use the built-in speaker from the mini ;-)

    1. Hello Robert! Thanks for the detailed explanation. I wouldn't have known in detail because I've never used a Mac in this mode. : D

  6. Hello Sir Apfelot and Robert,

    I am currently on a vacation trip and have not yet been able to answer.

    Thank you for your comments, that gave me some clarity. Even if it is technically possible to operate a Mac mini via an iMac, there are many small peculiarities in operation. I agree with Sir Apfelot that it is better to get a new iMac. The savings in hardware are small and not worth it.

    "To the question, what can the old iMac do that the new one can't":

    I can't say for sure either, but it's a stable, running system. Second, I am reluctant to part with a Mac HW that I have worked with problem for many years. Maybe after I have gotten to know my new iMac and have been able to port all software without any problems, I will finally part with it. That is how long I will use both computers.

    Thank you again especially Sir Apfelot and I am glad I came across this website.

    Chris

  7. Short correction:

    what I really mean is:

    ..with which I "problem-free" for many years ..

    but I think that came out of context.

    Chris

  8. Hello, I'm a Mac layman and I'm currently stuck.
    I have an iMac late 2009 which I use with a patch (http://dosdude1.com/mojave/) Mojave is running stably.

    We then wanted to run a Macbook Pro (TB connection) on the iMac via a miniDP cable. According to Apple site and Internet as well as here describe possible. However, the Imac shows nothing when switching with cmd + F2. He tries to switch and briefly (less than a second) a black screen and then back the old image from the iMac. Tried everything: switch from the login screen, switch logged in, fn + cmd + F2 ..

    Strangely, the connection between Macbook Pro and a Dell monitor from TB2 to miniDP (monitor) with DP cable goes without problems.

    Also from the Imac miniDP to (monitor) with DP cable went without problems.

    Just do not stop Macbook to Imac does not want.

    I do not know whether I am making a mistake in thinking somewhere or something else I have to pay attention to.

    I would be happy to receive advice and suggestions.

    1. Hello Saya!
      Thank you for your question. It should actually work if you have a 27-inch iMac. Apple's support document explicitly states the iMac late 2009 with 27 inches. Are you that size LG! Jens

      1. Hello, Jens!
        Thank you for your prompt reply. Yes, this is an iMac late 2009 with 27 ″. The Macbook Pro is from 2015 (with HMDI if relevant).

        1. Hello Saya! As Robert wrote, maybe it's just because you patched Mojave. This is difficult to clarify ... if you installed a macOS that is officially approved for your Mac, it could work. LG! Jens

    2. Hmm, since something happens at Fn + cmd + 2 at least shows that macOS recognizes something at the DP input, otherwise there is not even a short switch to black. But maybe he doesn't like the signal? Sorry, no idea, and trying to patch Mojave on my iMac late 2009 I will definitely not, because that could be the reason, right? ;-)

    3. Hi Saya,
      now I'm a little smarter again: it doesn't seem to be due to your Mojave patch, because I can't address the iMac screen of a 2015 MacBook Pro either. Like you, the iMac gets dark, but that's it. With my 2018 Mac mini as the source, it still works.
      Too bad, now I would have been happy about this solution, but I keep trying.

      1. Hi Robert,
        that helps me a bit. Now the colleague wanted to connect his MacPro (source) to the Imac (DPmini) via an HDMI / DPmini adapter. Do not think it will work, but I'll take a look and report.

    4. SUCCESS!
      I have just successfully displayed my new / used MacBook Pro 13 Retina from 2015 on the iMac 27 late 2009, as it should be!
      The trick: I tried the second Thunderbolt port. Plugged in and the iMac switched itself over. The iMac also switched to the other port, but only to black.
      I don't know if the two Thunderbolt ports on my MacBook are different, but it does seem so.

      1. Hi Robert! Thanks for the hint. That is interesting. I think I've read that there are also differences in the charging current, depending on which USB-C port on the MacBook Pro 13 inch you plug the connector. With the 15 inch model there is probably no difference. But that might also be an explanation for your phenomenon ...

        1. I used a DP mini to DP mini cable.
          To my shame, I have to admit that I told nonsense above: one of my Thunderbolt ports was simply defective, which I only verified with a Firewire adapter. A tab in the port was bent and was causing the problem.

  9. Dear Sir,

    thanks for the detailed instructions. Do you know whether this is also possible with a docking station? Background: I have a fairly new MacBook Pro and a fairly old iMac 27 (Mid 11). The old iMac is now completely at the end. Now I would like to be able to plug in and unplug the MBP as easily as possible, i.e. use the iMac as a monitor and have a keyboard / mouse on my desk, then plug in / clamp / switch the MBP and continue working.

    Any idea?

    All good wishes

    Guido Augustine

    1. Hello Guido!

      In principle, there is nothing wrong with doing it with a dock, as you say. It is only important that it is not a USB-C dock but a Thunderbolt dock, because the image transfer to the iMac does not work via USB.

      Here I picked out a few of the current TB3 docks:
      - ICY BOX Thunderbolt 3 Dock
      - Elgato TB3 Dock (Standard or Pro)
      - Belkin Thunderbolt 3 Docking Station

      What you use there is basically a matter of taste. All of them have a few bad reviews, but basically they should do the job for you.
      LG! Jens

        1. Yes, it works with that too. However, it is again one of the adapters that cannot handle 4K @ 60Hz. But if you don't play, but rather surf and use word processing, then you should only notice the 30 Hz if you move the mouse pointer quickly. But it's nice that everything works out for you! LG! Jens

          1. Damn. Since I've known that, I've seen it too; o) I'll test the other two options.

            What also annoys me: When the MB is removed, the connection is gone and I have to connect again with F2.

      1. Hello, Jens, that means with the ICY BOX IB-DK2102-C here (https://www.raidsonic.de/products/adapter_multidocking/multi_docking/index_de.php?we_objectID=5276) it does not work…? But that's what it says on the product description. Connected a new MacBook Pro 13,3" to it (MacOs 10.15.4) and want to control my old iMac 27" (2011) monitor with it. With my old 15” MacBook Pro it worked wonderfully (without adapter) with cmd+F2, now with the Raidsonic adapter (mini display port on the adapter, Thunderbolt on the iMac) unfortunately not... Does it have to be a Thunderbolt adapter?

        1. Hi Mac, sorry for the late reply. To be honest, I can't assess it, but mostly such hubs between the Apple-specific connections tend to cause problems. The Apple SuperDrive also doesn't like it when a USB hub is clamped in between. Nobody knows why that is, but it doesn't work. But I don't have any experience with the Icy Box Dock.

          1. Hello, Jens, unfortunately it really doesn't work - the dock doesn't let the protocol "through" that is necessary for the target mode - only works with a direct connection between MacBook Pro and iMac. A pity! And expensive (adapters...;-/

          2. Hi Max! I'm sorry ... but I thought so. Using the iMac as an external monitor is a very special thing.

  10. Hello Sir,
    Apple says that the Thunderbolt2 on the iMac2012 also functions as a mini display port, can it also record a MiniDP signal for iMac monitor use?
    thank you greetings from Berlin
    Ingo

    1. Hello Ingo! I'm not so sure. According to the table, your 2012 iMac definitely supports Target Display Mode. However, the cable you should use only says "Thunderbolt" and not a mini-DP cable. I would just test it if I were you and if necessary return the cable if it doesn't work. It would be great if you would let us know so that “we” would know if it would work! :D

  11. Hello Sir Apfelot,

    I have an iMac 27 ′, in mid 2011 with OS X Yosemite version 10.10.5, which I would like to use as a second monitor with a MacBook Pro Retina 15 ′, in mid 2015 with Mac OS X Mojave version 10.14.5. I have tried both a Thunderbolt to Thunderbolt cable and a Thunderbolt to HDMI cable and also with the help of the key combinations in the logged off mode. It just doesn't work.

    In the office, however, I was able to connect the MacBook to the 27 ′ iMac (2009) there without any problems.

    Do you have any idea??

    1. Hello Ksenia!
      So it should actually work with the iMac in mid-2011. Could you try all the USB-C ports on the MacBook Pro? With Robert, who also commented here, surprisingly it worked on one port and not on another. Maybe that's the case with you too?

      1. I connected it to Thunderbolt. Both connections did not work. Do you think I should get a USB-C cable?
        Could it perhaps also have something to do with the operating system, for example that the operating systems are “too far apart”?

        1. Hello Ksenia! Maybe I would try the USB-C Thunderbolt cable. Maybe that's the solution. The operating systems shouldn't be. It's clear that the 2011 iMac won't run Mojave ... and others will too. So it should be due to the wiring or something. Would be great if you report if it works with the other cable.

          1. I might do a backup and then try High Sierra. But please make a backup beforehand ... not that anything goes wrong.

          2. It has now turned out - somewhat embarrassing - I had the wrong cable. An Apple Thunderbolt cable helped (it probably had a Mini Display Port cable before). I didn't realize there was a difference there. I also have to press cmd + F2 on myself.

            Thank you and greetings

  12. just to be on the safe side - or: before I throw myself into expense ...

    Hello Sir,
    I've looked and read a lot, but somehow I still couldn't find one thing: iMac 2011 as an extension (monitor) on the iMac 2019. The latter came today ...
    I keep tripping over the statement that 5K Mac's won't work as a monitor. Wouldn't be the case for me... But does “He” support this mode? In other words: can I connect my 2011 to my 2019?
    I just have to buy the TB2 / TB3 adapter and a TB2 cable.
    Thanks and best regards!
    Guido

    1. Hello Guido! I just discussed this with a colleague and he said it would work. The corresponding Apple support page calls the feature “Screen Sync Mode”.

      But you need two parts for the connection:
      - TB3 to TB2 adapter (here at Amazon)
      - TB cable (TB2 connector) (here at Amazon)

      I linked the originals from Apple because I don't know if the third-party cables and adapters work properly here.

      1. Hello sir, supie, thank you very much!
        2×27″ looks mighty :-) I thought long and hard about sense and nonsense, but throwing it away or selling it for almost nothing... didn't mean anything to me either. Better invest another Hunnie then.
        LG Guido

    2. Feedback:
      Everything great. Works without problems.
      19er connected to the adapter - since the 9er "only" has TB3. TB2 cable on and “plugged” into the 11er. Hunched wildly on the keyboard… Tadaaaaa!
      Even if they are named or labeled the same, there is that slight difference between “left and right of the spacebar”. ;-)
      What can I say ? It's brilliant. Once a huge display area and then the option to reactivate “the old one” via a key combination if necessary.
      So no wrong decision.
      Thanks again for your help.
      VG Guido

  13. Hello Sir,

    Which 27 "monitors are recommended as a second monitor for the 2019 27" iMac Pro?
    I connected an old Dell U2410, which works, but "overexposes" severely, cannot be controlled via its menu. It worked with a Thunderbolt to HDMI connection.

    Best regards,
    Jeans

    1. Hi Jean! I don't think there are any official recommendations from Apple. I've never known anyone who has an iMac Pro either. Therefore, I cannot report from my own experience ...

      Basically, however, the cable can also be problematic (I've read). There was the recommendation, this one USB-C to Displayport (4K @ 60Hz) cable from Choetech.

      One monitor recommendation that I also found was that EIZO EV2785-BK, because it has a high pixel density and thus comes close to the dipsplay of the 5K iMac or the iMac Pro.

      I hope I could help you a bit with that.

  14. Hi Sir Apfelot, thanks for the helpful article and replies to the comments. Do you think I have a chance to use a 27 ″ iMac (2013) as a display when both TB connections (ex works) are without function? Thanks and best regards Romy

    1. Hello Romy! Sorry for the late reply. I think if the connections don't work, the image transfer won't work either. But maybe you have a friend with a Mac that you can test it on?

      1. Hello Sir Apfelot, thank you very much. It doesn't work with screen transfer. But very good and satisfactory with AirServer. Great tool! Sincerely, Romy

  15. Hello
    I did that too. However, I have to re-register the iMac as a screen every time. That means after each use of the screensaver, press the keyboard commands cmd / f2 again. For me that also means changing the keyboard every time. Isn't that easier? So that the iMac always recognizes itself as a screen as long as the MacBook and iMac are connected?
    Thanks for helping!

    1. Hello Katja! I don't know how to "turn it off", but switching the keyboard can be solved with a Bluetooth keyboard that can connect to multiple devices. For example, this would be the "K380" by Logitech. Perhaps that will help you resolve the matter more comfortably.

  16. Dear Sir Apfelot,

    Thank you for the article first, I used it to connect my old mid-2011 iMac to my beautiful new MacBook Pro 2019 spaceship. And: I am completely enthusiastic.

    Unfortunately, the old Apple wireless keyboard cannot be connected to the MacBook if I had to use it for switching beforehand and the iMac is somehow still "on". Is there a way to disconnect the Bluetooth keyboard from the iMac and use it for the laptop?

    Best regards and thanks: Nora

    1. Hello Nora! I'm glad it worked out with the iMac. Disconnecting and re-pairing the Bluetooth keyboard is relatively easy. At the top right, on the side is a round button. Hold this down for a few seconds until the green LED on the top of the keyboard flashes. Now go to System Preferences> Bluetooth on the MacBook Pro and pair the keyboard there, which should now be visible. LG! Jens

      1. Oh wow, that was a wonderful demonstration effect: according to your description, I have always tried exactly that before, without success - but now the keyboard was gracious and has connected and I'm happy.
        Thank you for the confirmation! And the help. :)

        1. Well fine! Everyone knows about the demonstration effect. I always feel the same when I ask others for help. : D

          1. Good morning Jens, unfortunately the feat only worked once. If I stop mirroring the MacBook to the iMac and then try to connect the keyboard, I also see exactly how the iMac snaps the connection before the MacBook can. (“Keyboard connected…”)
            Is it possible to prevent that and force the desired new connection? Asks and greets: Nora

          2. Hello Nora! Yes, you would have to permanently kill the connection to the keyboard on the iMac. You can do this via System Settings> Bluetooth, then select the keyboard and delete with the cross on the right. Then the keyboard should only couple with the one on their Mac.

          3. Thank you very much for taking the time to help strangers online! Unfortunately, I can no longer trigger the desired synchronization when the keyboard is completely disconnected. Maybe I'll have to get some old wired device to do this. Best wishes! :)

      2. Good afternoon Sir Apfelot,

        Thank you very much in advance for your article, thanks to which even a technician like me now knows what it takes to use an old iMac as a monitor. Before I buy an old iMac (mid 2011) to use as a monitor for my MacBook Pro (2018), I wanted to ask one more question about the keyboards:

        As I understand it, I only need the iMac's keyboard to enter the key combination to activate screen synchronization. As soon as this synchronization has taken place, everything runs via the MacBook Pro and the second keyboard connected to it. Is this assumption correct?

        It would be my wish to use two keyboards, because the wireless Magic Keyboard (2017) - which I have been using so far for input on my MacBook Pro and would like to continue using it for screen synchronization - according to the Apple website, does not work with an iMac ( mid 2011) is compatible.

        I hope to have asked my question in an understandable way and thank you for your help.

        Greetings from Switzerland,
        Bernhard

        1. Hello Bernhard! Yes that's right. You only need the keyboard for booting and for the key combination. Then you can decouple them, put them away or do something else. However, you will have to press the keyboard shortcut every time you restart your iMac. As an alternative to two keyboards, you could also use a Bluetooth keyboard that can be paired with several devices. I think this should work.

  17. Hello.
    i have an imac late 2013 and an asus zenbook (both computers have win 10). I would like to use the imac as a screen, but after a long search I didn't find any results which cable to choose for the connection. imac has thunderbolt 1 and laptop usb c. is it possible to use a normal cable usb c to display mini (https://www.amazon.de/gp/product/B07PGJXZGH/?tag=sirapfelot-21) to use. Thunderbold should be backwards compatible?
    Thanks in advance.
    best regards
    michael

    1. Hi Michael! This is not going to work. This connection to the iMac is not a simple cable like a monitor. The function is regulated by macOS and that would have to agree with your Asus Zenbook with Windows that it displays a monitor image. Apple certainly didn't implement that as it isn't even supported by all Macs. So: I don't see any chance there.

      1. Many thanks for your response. Is there no possibility at all, not even by means of other cables, adapters, possibly even programs?
        lg

        1. Hi Michael! I don't know of any solution. But that doesn't mean there isn't one. : D Maybe another reader has an idea ...

  18. Hi all,

    I have an iMac 24 inch in early 2009 and now want to use the iMac screen as a monitor for my MacBook Pro Late 2016.

    I connected the two devices with a Thunderbolt (on the iMac) and HDMI via a multiport adapter (on the MacBook).

    When I click on monitors on the iMac, no other screen is recognized.
    Clicking the Option key and then "Detect monitors" didn't help either.

    The key combinations: cmd + F2 OR cmd + fn + F2 didn't work either.

    Can someone help me? What am I doing wrong?
    LG Linda

    1. Hello Linda! There was never a 24-inch iMac model. I suppose that was a mistake, but your model is just probably not one of the ones that supports the feature. LG

      1. Hallo,
        but it's actually a 24-inch iMac. It says so under About This Mac. Well, then I guess I have to live with the fact that this iMac doesn't support the function. Thank you for answering anyway.
        Hello Linda

        1. Hello Linda! Yes, the ad doesn't lie and I've learned something again: there are 24-inch iMacs. : D But 24 inch models are definitely in the list of supported devices. For that reason it will unfortunately not work ... :(

  19. Great article. First of all, thank you for that!

    I have the problem that I connected my 27 “iMac from 2012 to the 27“ iMac from 2019 with the - Thunderbolt cable and the corresponding adapter on TB3.

    When I boot up both computers and then press my 2012 cmd + F2, the display goes completely black. However, I see that he takes over the screen from the 2019. However, I can't get the brightness. Does anyone have a tip for me?

    1. Hello Keliki! Unfortunately, I have no idea what that could be and how to increase the brightness. But maybe another reader has a tip?

    2. Hello Sir Apfelot
      I have a late 2012 27 “iMac and would like to use it as a large monitor for my Windows computer with HDMi or VGA connection (thanks to Corona and home office).
      As you know, my iMac has two Thunderbolt 2 ports.
      On my first attempt using the MiniDisplayPort and HDMi adapter, my iMac made no attempt to detect any external device.
      Is there a Thunderbolt 2 to HDMi or Thunderbolt 2 to VGA adapter or do you have to take a different route?
      I look forward to your feedback

      1. Hello Keliki! Unfortunately, there is only bad news. It's not a question of the cable, but of the software or hardware support of the iMac. There are few models out there that can use another Mac as an input signal, but I'm pretty sure Apple and Microsoft haven't talked about how to use an iMac as an external monitor for a Windows computer when it doesn't even work with every Mac goes. So unfortunately you won't find a solution there. But take a look here in the blog post I wrote something about cheap second monitors.

  20. Bernd Hebebrand

    Good day,
    I use an iMac 21 ″ privately (mid 2011) with which I am super satisfied (i7 and 16 GM RAM really okay for my needs)
    In terms of work, I have to use a Win-PC / Notebook and now I have to use the iMac as a screen for my Win-Notebook in the home office for reasons of space.
    A connection via mini display port did not work ... what can I do?

    VG Bernd

    1. Hello Bernd! Unfortunately there is no way. Windows and Mac don't collapse like this. The two operating systems have to coordinate this and unfortunately Windows and macOS do not do that with regard to this coupling.

  21. Good day everybody,

    Since the coronavirus, I have had my Imac 27 model at home at the end of 2015 so that I can work from home.
    I have the same model as a private home, how can I use two Imacs as a second monitor. Can someone help me there, please

    1. Hello Erol! I don't know what to say. You posted your question right in the post that explains how to do it. If this doesn't work for you, you may not have the iMac models that support this feature.

  22. Hello Jens, Thank you very much for the detailed information about the screen synchronization mode. I've been using the mode for a long time with a MacBook Pro and iMac 27 "(Late 2013). What I'm missing: I would like to use the iMac's built-in camera for video conferencing. The MacBook Pro or Skype & Co. only recognize the integrated camera on the MacBook Pro, but not that of the iMac. Is there any way I can use the iMac camera when the screen sync mode is on?

    1. Hello Rainer! Unfortunately, screen sync mode isn't something Apple has actively pursued. That's why it only works with old iMacs. I've been looking but couldn't find a way to use the internal camera of the "external" iMac as a webcam. The data just isn't sent back down the connecting cable. :-(

      1. Hello Jens, thanks for the quick answer! Then all that remains is to clamp an external camera on the iMac and connect it to the MacBook Pro ... ;-)

  23. Hallo,
    I would like to use my 21,5 ″ iMac late2012 with El Capitan as a second display for my MacBook Pro (Retina 13 inch, early 2015) with Sierra. According to the list, this would have to support you the TDM. I tried to connect it with an Apple Thunderbold cable. When I press cmtd-F2 it does not happen, only a short error signal tone sounds. Why is it that this is not working? Greetings Tobias

    1. Hello, tobias! To be honest, I'm overwhelmed by that. Your iMac model should be able to. Would be interesting why he makes the error tone.

      1. Whew, I still managed it. The trick was the keyboard.
        I had first connected an old Apple cable keyboard to the iMac (the white one with the plexiglass run on the outside) because my original wireless keyboard was broken. Then I bought the original Apple keyboard. And lo and behold! It works!

        1. Yes, I still have this USB keyboard with the transparent Plexiglas here. It has the cute nickname "crumb drawer" because everything collects in it so nicely. :D Great that it works for you now.

        1. Hello, tobias! I think it won't work with the Dock or Windows. It's an Apple-specific thing and has nothing to do with the normal Thunderbolt 3. Even with Max (see other comment) it didn't work out, despite using a TB3 dock and another Mac.

        2. The BlackMagic material is actually at home in the prosumer / professional sector, that is to say it is for people who more or less earn their money with video.
          The answer is "yes", you get the video output of a Win computer on a Mac with the recorder. But there you need an appropriate program to see what arrives from the Win computer at all. And then the whole thing has more of a feeling of a virtual machine.

          1. Yes, you may get a picture here with gadgets, but that certainly has nothing to do with the connection that two Macs make. I strongly assume that the latency alone with the Win-to-Mac solutions with the Black Magic part would be significantly higher.

          2. You're right, it has absolutely nothing to do with connecting two Macs.

            The BlackMagic parts are really fast and have maybe 3-5 frames of delay. But in the end they are just boxes to get video content into a computer with a Thunderbolt connection (e.g. for any streaming stories). He could also buy a USB video grabber / capture card.

  24. Hi, thanks for the great report, but it doesn't work for me at all. I have an iMac 27 mid 2011 and a MacBook Pro 2018. The cable I'm using was bought from Amazon. The designation “CABLEDECONN USB-C Type c to Mini DisplayPort/Mini DP 4K 60Hz Resolution Active Cable Adapter 6FT with Aluminum Case Compatible with New MacBook Pro 2017 Samsung Galaxy S8 A0303”

    1. Hi Michael! This doesn't work because you bought a USB-C cable. You explicitly need a Thunderbolt cable. For one purpose you unfortunately also have to work with an adapter, since the iMac does not have the flat TB3 connector. So you need that Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter and another Apple Thunderbolt 2 cable. That should work, but it would be great if you could give us some feedback. Then I would add that in the article above.

      1. Hi, thanks for the quick reply. Yes, then I'll probably order it that way. If it works, I'll be happy to let you know. LG

  25. Hello, thanks for the good explanation. I have a MacBook Pro (Mid 2012) and would like to use my iMac 27″ (Mid 2010) as a display. Is there a Thunderbolt to Mini-DisplayPort cable? Or do I need an adapter?
    Thanks for the help. LG

    1. Hello Alexandra! I looked for such a cable but found nothing. For this reason, I would also recommend the solution with the Thunderbolt 2 cable and the adapter. That should actually work.

      1. Hello and thanks for the quick reply. So then I need these two cables from your comment on April 28.4th: ​​Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter and another Apple Thunderbolt 2 cable.
        Sorry, I just can't make out connections ... LG

        1. Hello Alexandra! Sorry for my - unfortunately wrong - answer. Your old MacBook Pro doesn't have a USB-C. The iMac from mid-2010 didn't have Thunderbolt yet. For that reason, a perfectly normal Mini Displayport cable (without any adapters) would have to do the job. Here that from CableMatters for example, should go. If you have tried it, I would be happy to hear from you as to whether it worked. But should actually ...

          1. Hallo,

            I still wanted to report back. The original question was: I have a MacBook Pro (mid-2012) and would like to use my iMac 27 ″ (mid-2010) as a screen. I have bought this cable from Gravis.

            It worked immediately, when plugged in, the iMac immediately became the “monitor” of the MacBook, without any further shortcuts, etc.
            Thanks again for the help.

          2. Hello Alexandra! Thanks for the feedback. That's good to know. I didn't think a simple mini DP cable would work. But it may be that you have the "advantage" of not needing an adapter with your constellation. Your iMac and MacBook Pro share the same connector. This is not the case for many others. They usually have a USB-C on one side and a mini DP port on the other.

  26. Sir Apfelot, thank you very much for this great article!
    I've read through all of this, but I'm a little confused now and ask for help too!

    Goal:
    iMac (27-inch, late 2009)
    as an external monitor for
    MacBook Pro (13-inch, 2016, Two Thunderbolt 3 ports)

    Electric wire:
    MacBook +> USB C to HDMI / USB / USB Type-C Hub Adapter +> HDMI cable +> Mini DisplayPort Adapter to HDMI => iMac

    The wiring mentioned above does not lead to success….
    What should i replace? What do I have to buy new?

    Thank you!

    1. Hello Catya! Unfortunately, I'm speaking without any practical experience here, since I don't use an iMac from , but I think the main problem is that the USB C HUB physically "rebuilds" the connectors to fit, but the signal doesn't get through. You would have to Apple Thunderbolt 3 to Thunderbolt 2 adapter and Apple Thunderbolt 2 cable to get. I think it should work with that. If you give it a try, it would be great if you let me know whether it worked. Then I know that my recommendations are not nonsense. : D

      1. Hi.
        Bought cable but it doesn't work. Command + F2 / command + fn + f2 doesn't want to.
        The keys F1 / F2 etc. used as standard function keys, tried the whole thing with: both computers switched on and logged in, MacBook logged in - iMac not logged in to the user, restart the startup volume in hard disk mode but command + f2 doesn't want to either.

        Cables are new and from Apple, connectors work ... what could be the problem? what else can I try?

        1. Hello Catja! Is your iMac in the list of supported models? That would be the first thing I would tap. Otherwise you can't really go wrong. :(

          1. Yes, it should actually be compatible. Unfortunately, I have no more idea what it could be. The Apple cables are 100% compatible, but maybe another reader has a tip on what to test?

          2. At that time, one of the Thunderbolt ports on my MacBook Pro was defective, that fooled me. But that was TB-2, so it can happen sooner (metal tab was in the way).

            Then a very stupid question: you pressed the buttons on the iMac, right?

          3. I have now found out that iMac Late 2009 does not have Thunderbolt, now I have to try Mini DisplayPort, there is for example
            LMP USB-C 3.1 to Mini-Displayport cable
            an idea whether such a direct cable - without an additional adapter, could work?

          4. Hello Catja! With these cables, I honestly don't know for sure whether it will work. One reader has had a good experience with a mini DP cable (it says somewhere in the comments), but a direct USB-C to mini DP cable has (as far as I know) nowhere worked. The variant that is a bit more expensive, but probably has the highest compatibility, is the Apple TB 3 to TB 2 adapter and then that Apple TB 2 cable.

  27. Hello
    I have an imac 2011 27 inch model that I want to use as a second monitor for my surface book 2. what kind of connections do i need?

    1. Hello Drilon! I can't give you 100% information because I haven't tried it, but the connection sometimes fails when you connect two Macs via a Thunderbolt 3 hub because the "monitor Mac" does not recognize that another Mac is sending something . 99% of the time, the right signal is not coming from Windows devices. I'll leave the 1% because I haven't tried it myself, but as far as I know, this connection is an Apple thing.

  28. Hallo,
    Thank you for the great and detailed article. I even have a question now. I have a MacBook Pro (13-inch, 2018, four thunderbould 3 ports) and an iMac (Retina 4K, 21.5-inch, end of 2015) that I would like to use as the second display on the Macbook. It is now not clear to me whether this works, at apple on the website it is stated under by the end of 2 2015 inches that no longer works. but what about the 27 incher? I would appreciate a quick reply
    Greetings and stay healthy
    Leon

    1. Thank you for your question and your praise.
      Unfortunately, no 2015 iMac works. No matter what size. It's only the older Macs that still have this mode built in. Sorry :-(

      1. Wow thank you, the answer was really quick.
        Oh dear. that would be one of the practical things for the home office
        do you know an alternative solution? the i mac is unfortunately very slow and so no longer useful for me. I work in the design sector, I work a lot with Adobe programs and 3d software. he just doesn't take part anymore. I already reset it, but unfortunately that doesn't really help.
        Would like to have access to the bigger screen but use the more busy and processor of my Macbook.
        Greetings and thanks again for your quick reply

        1. Hello Leon! Unfortunately, there is no alternative to using the iMac as a monitor. But you can pimp the iMac with an external SSD quite cheaply. I had already recommended this to a reader recently, who thanked me overjoyed for the tip because the Mac now feels like a new computer. You can do this with an external SSD such as this one from SanDisk use and then via Carbon Copy Cloner or Super Duper copy everything to the SSD. Then select the SSD in the system extensions> Startup disk and restart the Mac. The first restart could still be slow, but the second restart at the latest should be quick. And working with the iMac should feel good too.

          1. That sounds great is ordered directly. Thank you for the great tips. I'm really excited about your side, really strong. I'll get back to you when I've tried it and report ^^

          2. That pleases me! If you have any problems with cloning, just report it. The SSD is presumably pre-formatted in ExFAT. You would have to change this to the format of your startup disk before copying. If you're using Mojave or Catalina, it's APFS, otherwise it's case-sensitive Mac OS Journaled. But as I said: just report if something is stuck somewhere.

    1. Hello Uli! The problem is: The Elitebook is not an Apple computer. It only works on Macs ... not between PC and iMac.

      1. Hallo,
        Many Thanks. There is no clear statement on the web, for example
        [Link removed from sir]
        For me it also makes sense if there are cables for it.

        Greeting Uli

        1. Hello Uli! I have now looked through various forums again and there are always people who say you have to install this and that card on your PC to make it work. The people who do it then write across the board that it didn't work out. For this reason I stick to my statement: iMac as an external monitor for a Windows PC does not work with a cable or adapter. I also removed the link in your comment because it explains how it supposedly works, but it just doesn't work - this is shown by the reports from people who have tried it and ask in forums what it is now related to.

    1. But of course. I like to be convinced otherwise if someone actually manages it in practice, but all forum posts that I've read show something else. : D So better save money and return cables.

      1. Dear Sir Apfelot,
        - (I would have read earlier in your forum) -
        I can also confirm your statement: "iMac as an external monitor for a Windows PC does not work with a cable or adapter".
        Also NOT with the following setup:
        iMac 21.5 mid-2011 with Thunderbolt interface, PC mainboard with Thunderbolt header and plugged-in Thunderbolt 3 PCIe adapter card with connection for the PC graphics card (the PCIe adapter card provides the video signal from the graphics card for the TB3 interface to monitor monitors with TB3 Input), TB3 to TB2 adapter from Apple for connection to the iMac.
        DID NOT WORK!
        But maybe it's something like Fermat's last sentence: As long as the impossibility is not proven, there will be repeated attempts to see whether it might work after all. (Fermat's theorem was only proven after 300 years, so keep the thread open!)

        1. Hello cave! Yes, there is something about Fermat's theorem. : D And thank you for contributing a few more variants that DO NOT work. : D

  29. Hallo,

    First of all, thank you Sir Apfelot for this thread, great!

    Also at the risk of having missed something above, I ask for your help, as I may have gotten confused with the cables.

    I would like to use the iMac 27 ″ at the end of 2009 as a second monitor on my 2 2019 ″ as an extension.

    I tried the Apple Thunderbolt 3 to Thunderbolt 2 adapter, which is also linked at the top.

    Then I tried the Apple Thunderbolt Cable (also linked above), but unfortunately nothing works. Then I took the mini display port cable instead of the Thunderbolt cable, and no reaction either.

    Settings as described here several times: new iMac registered, old iMac 2009 in the login screen.

    Now a really stupid question... the F2 key is brightness, right? With this I can only increase the brightness on the Apple keyboard (the "Standard function keys" setting is deactivated), or do I have the mega board in front of my head in terms of keys?

    CMD + F2 only comes the nice error tone from the iMac 2009.

    Can you possibly help me?

    Thanks and Regards

    Torsten

    Then n

    1. Hello Torsten! From the cables everything should be correct. Regarding the F2 key: You should have an "fn" key on the bottom left of your keyboard. You press this at the same time as the F2 key so that it doesn't change the brightness, but executes "F2". Does this work?

        1. Hello Torsten! This is strange ... your iMac should actually support the mode. Can you continue to update macOS on it? Unfortunately, I have no clue whether macOS is doing anything at all, but that would be my only tip as to why it could be.

  30. Hello Sir Apfelot, hello Robert,

    Thank you very much, no, unfortunately no solution either. Always just the monotonous error tone. Just checked for updates to be on the safe side, everything is up to date. High Sierra 10.13.6 on 27 ″ at the end of 2009 ... everything fits together with the Apple article on this subject.

    It's a shame ... because it should work ... and here in the thread there are really many options and it worked for many.

    Is there a system setting somewhere that can accidentally deactivate the function or something?

    Do you know anything like that?

    Thank you very much again!

  31. Hi all,

    the 3rd cable variant finally actually worked ????

    The solution was the direct MiniDisplayPort to USB-C cable. Just plug it in and the iMac Late 2009 switched over automatically.

    I didn't know THAT before ... that cables from external manufacturers work better than the original Apple adapters / cables.

    Here is the link to the corresponding cable that worked for me now:
    CableDeconn USB Type C to Displayport

    It works, wonderful! Now I first have to return various cables and adapters ????

    1. Hello Torsten! Thanks for the link. I'll use it at the top of the article so that others don't have to search long. It's great that it works for you!

  32. Hello Sir Apfelot,

    I hope I haven't read anything above ...
    I would like to use my iMac 27 ″ in mid-2010 as a monitor for my wife's Windows computer, because I have a new iMAC and the old one can still be good for something.
    I bought a 3in1 mini display port to VGA HDMI DVI adapter from CSL.
    I have already tried it via HDMI and / or VGA with Command + F2 and / or Command - FN - F2 both in the login screen of the Mac and logged in.
    The MAC screen then jumps to a poorer resolution mode, but I can still see the Mac's desk there ... after a few seconds it jumps back to the higher resolution screen.

    Any idea?
    I'm a little desperate because it should actually work; (
    Is it possibly the cable?

    Thanks in advance and best regards
    Chris

    1. Hello Chris! Unfortunately, this mode, in which the Mac functions as an external monitor, does not work between Windows and Mac, but only between Macs. What happens to you is as follows: The Mac thinks that an external monitor is connected to the HDMI port on which it should display its image. Since this does not seem to support the high resolution of the iMac, it switches to a lower resolution and outputs its image via the mini DP port. So unfortunately that won't work for you - no matter which cable you use. The Mac hardware is here across the board.

  33. Hello Sir Apfelot,

    I also have problems connecting my MacBook Air 2020 to my iMac 21,5 Late 2011.
    In the meantime I have tried all possible cable configurations suggested here. The most expensive Apple connection Thunderbolt 3 adapter and Thunderbolt cable does not work either. I'm so slow with my Latin at the end. Is it possible that the target display mode no longer works with macOS Catalina?

    Regards
    Jens

    1. Hello, Jens! Unfortunately, I don't use Macs with it, but I do here Read in this thread that macOS Catalina was the solution for some people because there was a bug with the TDM under High Sierra. So actually it should work under macOS Catalina ... no idea what it depends on you. :-(

  34. Hello Sir Apfelot,

    Thank you for your prompt reply. Unfortunately I cannot install Catalina on my iMac late 2011. It's really bad ... that it doesn't even work with Apple's own adapters.
    There has to be some solution?

  35. As I just found out, it no longer works with catalina. Apple is annoying me extremely slowly, maybe I should turn around after 15 years of Apple.

    1. Hello, Jens! The link you posted in the comment unfortunately resulted in a 404 error. Could you send it to me again? As far as I could read, it should still work under Catalina.

    1. Hello, Jens! Thank you for your hint. On the Apple side it is really clear: The target display mode no longer works with macOS Mojave and Catalina or even newer systems (such as Big Sur soon). That is actually a shame ... but it was also a little specialty that was only used by a small target group. Unfortunately, you are one of them. :-(

  36. Hello Sir Apfelot,
    A few weeks ago I bought a new MacBook Pro (13 ″ / macOS Catalina version 10.15.6) and now I want to use my old iMac (27 ″ / mid 2010 / OS X El Capitan version 10.11.6) as a screen. I bought a cable (USB-C to Mini Display Port), as has already been mentioned several times in various comments. When I plug in the cable and press the appropriate key combination, the iMac's screen goes black and stays black. Actually, all requirements that have been described should be met, but the connection does not seem to work. Do you have any idea what could be the cause? I've read through (most) of the comments, but haven't gotten any smarter.

    1. It's actually a good sign that he's responding to the key combination. That means you probably only have one cable that isn't working. Maybe you will try again with another one linked here. Unfortunately, I don't have any more tips. : D

    2. It doesn't work with Catalina and the MacBook Pro / Air 2020. Apple has switched off the target display mode from Mojave, see my link above.
      I have the same problem and now have to buy an external monitor.

      1. Thanks for the hint. I add Mojave to the article so that the other readers with Mojave or higher do not have any more hopes.

      2. Fortunately, this only applies to the hardware mentioned (Air 2020).
        Catalina on my MBP 13 ″ (Early 2015) still works well with my iMac, if I know anything else about Big Sur, I'll get in touch.

        1. Hello Robert! Yes, then the Apple support entry probably means that the iMac that is used as a monitor must not run with Mojave. But thanks to the old hardware we have with the iMacs, that should seldom be the case. In a pinch you just have to install High Sierra on it again.

      3. Maybe I misunderstood you, but OS limitations only apply to iMac. If High Sierra is running there, it's not possible since Mojave, that's true. As far as the MacBooks from 2020 are concerned, I can't check that, on my "old" MBP 13″ 2015 as a source, it's still possible even with Big Sur (Beta).

  37. Melanie Bartels

    Hello Sir Apfelot,

    Today I took my new Mac Book Pro “15” from work to the home office. At home I have an old iMac (21.5 inch, mid 2011). Now I hoped that everything would work with "CABLEDECONN USB-C Type C to Mini DisplayPort/Mini DP"...but unfortunately nothing comes with cmd + F2...not even with cmd + F2 + FN ;-(

    Can that be due to the cable? What else could I try?

    LG
    Mel

    1. Hello Mel! We heard from another reader that it could also be due to the system running on the iMac that is supposed to act as the display. Do you happen to have Mojave or something newer on it? LG

    1. I think Target Display mode is still running under High Sierra. It only seems to have disappeared under Mojave. Then it can really only be due to the cable. But I can hardly make a recommendation here, because if I look at the comments of the other readers, then for some the one USB-C to mini-DP cable works for others, the solution with the Apple adapter and cable. But what will work for you is difficult to predict. :(

    2. Hi Mel,
      same constellation as mine. It no longer works with the new MacBooks. No matter what kind of system is installed.

  38. Melanie Bartels

    Hi Jens,

    does that mean it doesn't work at all? ;-( or should I order the Apple cable with adapter?
    Thunderbolt 2 cable from Apple (0,5 m or 2,0 m) &
    Thunderbolt 3 to Thunderbolt 2 adapter

    LG
    Mel

    1. Hi Mel,
      even with the adapter 3/2 and Thunderbold cable it no longer works. I bought it specially. Now there are € 80 cable scrap lying around here. I've tried all the options on cables, it no longer works with the new MacBooks.
      A MacBook from 2009 with an adapter 3/2 and Thunderbold on the iMac 2011 works fine. I also tried the MiniDP on DVI (Original Apple) plus DVI on TB3. Everything does not work.
      I have now bought an Eizo monitor in order to be able to work properly at all.

  39. Hello Jens,

    I have now read the entire course and see such creative and good approaches to the further use of not so up-to-date hardware. Therefore I dare to ask the following question:

    Connecting iMac and Windows works in this case?

    iMac beginning 2009 27 “with HP Envy Convertible 15

    Many say there is no chance but I don't like to take it completely;)

    Thank you for your feedback signal
    Sabine from Graz

    1. Hello Sabine! So with a cable it doesn't work between Windows and iMac. The only way I could think of would be to use a remote desktop application like AnyDesk. So that you can control the PC remotely via the iMac and see its screen. But of course this is always associated with a slight delay in the display and the input of commands, which can interfere with everyday work. I would not recommend it ...

  40. Hello, Jens!
    Thanks for your thread. This has already been helpful, but do I still have a question? I recently bought a completely new iMac 21 ″ (model A1418) Mac OS Catalina. However, I still have my old iMac (model mid 2011) Mac OS High Sierra, which I use as a second screen for my new iMac.
    The two iMacs are connected with Thunderbold.

    The key combination (cmd) + (F2) performed on the old iMac and my new iMac in use as the main screen. I performed the key combination on the old computer because it doesn't seem to work on my new iMac.

    Now to my problem:
    Everything works very well in operating mode. I'm using the keyboard from the old iMac on the new iMac.
    When I shut down my iMac, both screens close, but my old iMac goes back to operating mode and then I have to switch the keyboard again so that I can shut down the old iMac. This is very annoying because I only want to use my old iMac as a screen and no longer as a PC.

    Apparently the synchronization mode doesn't work either or I misunderstood something. Please provide specific help.

    Thanks for your feedback
    GlG Roland from Vienna

    1. Hello Roland! To prevent or make it easier to move around, you could use a keyboard like the Logitech craft that can be connected to up to three devices. I don't know of a solution via macOS now. LG

  41. Hi Jens,
    thank's for the Tipps!
    I had a working system consisting of MacBookPro from 2018 / macOS 10.14.5 and iMac late 2013 / macOS 10.10.5.
    Then I have the iMac on 10.14.5 as well. updated and now the monitor function no longer works, I had a long phone call with Apple Support, in the end they said it would go up to Mac OS 10.13 at most. High Sierra on the iMac. Unfortunately it still doesn't work.
    Do you have experience with this problem or do you know up to which OS it could work?
    (I don't want to use PS 10.15 yet because important software is then no longer available)
    Thank you very much
    Greetings from Munich, Marian

    1. Hello Marian! I think it should actually work out easily with macOS 10.10.5. Could you have recently updated the MacBook Pro when it suddenly stopped working?

        1. Ah ok! That could have been it. But unfortunately I have no idea up to which OS should work. Maybe you still have a backup of 10.10.5 so that everything works out again for the time being? Then you could try an update to 10.11 and see whether the iMac still works as a monitor.

  42. Hello Appleot, Community,
    I'm just searching the internet and can't come to a clear conclusion. Can I connect my 2020 Macbook to the 2013 iMac?
    Then with 2 cables. So Thunderbolt 3 to 2 adapter and then the Thunderbolt 2 cable?
    I think I read on the Apple Support website that the path no longer works for the 2020 model.
    Does anyone have the same setup and can you report from experience?
    VG, Markon1

  43. Hello.
    At the moment we have the problem that our iMac (27 inch 2012) no longer wants to start and we would still like to save the data.
    The report sounds really very good ????
    As I read it out, the second car has to show the login screen, which ours unfortunately no longer does.

    Do you also have a tip? We still have a 27 inch from 2010 and it works.

    Thanks and greetings from Hamburg
    Sascha

    1. Hey Sascha! If the Mac does not start anymore, using the iMac as a monitor will not help you, as it will still prevent you from accessing the data. So you would either have to try to boot with another hard drive or remove the hard drive. Greetings from Northern Hesse!

  44. Hi all,
    I don't know if the question has been asked here before. I have an iMac 27 ″ (late 2015) and a MacBook Air (2013). I would like to pair these two devices and use the MacBook Air display as a second display. What options do I have here? I first connected both of them with a Thunderbolt 2 cable. When pressing the key combination cmd + F2 or cmd + fn + F2 nothing happens. I have also read that this function is supported on iMac's younger than late 2014. Do I have other options for using the MacBook Air display as a second display for the iMac?

    I would be very happy to receive answers.
    Regards
    Ralf

    1. Hello Ralf! Unfortunately it doesn't work in the "direction". The iMac can only be the display. Unfortunately, a MacBook Air can only “send” but not “receive”. Unfortunately I don't have any good news. There used to be a hardware solution that could connect two Macs, but unfortunately I can't remember the name. :( Was a kind of wireless connection between one Mac and the other. As a result, it was unfortunately a bit delayed... but maybe still tolerable.

  45. Hello Sir Apfelot,
    I don't want to start all over again because this topic has been described many times before, but I'm pretty confused and desperate about what should work and what shouldn't? Topic iMac as a display: There are as many reports on the net as easy to do (just not for me !!) I would like to use my iMac (Mid 2011-21,5″ - Sierra) as a display for my new MBPro (2020 - Catalina). Bought the original TB 3 to 2 adapter, bought the original TB cable, tried all key combinations and previous tips: nothing works! – Key cmd+F2 without function! Can only play the screen from MBPro to the iMac via screen sharing, but not as an additional display and in a botched view. (By the way, it also works in the other direction). What does "BootCamp doesn't work for this function" actually mean? I am using Windows via BootCamp. I know it doesn't work on Windows. It's everywhere. But what does that mean? There must be no Windows on the computer which is installed via Boot Camp, or not Windows in use? I only want to use the screen for Mac OS! Would it possibly work if Windows is only on the computer via Parallels? Am I correct in assuming that max. High Sierra can be on the old iMac and not BOTH Macs are meant? The topic is pretty annoying. According to Apple, everything is very easy and now I have probably once again paid idiot tax (approx. €100.-) for the adapter and cable that you don't need otherwise.

    1. Hi Andreas! Unfortunately, the user reports are very, very different. There are also readers who can use the iMac as a display with a 2020 MacBook Pro. But don't ask me what's the catch. Unfortunately, I don't have a Mac available and I can't test it. I can't really imagine that it's up to you to boot camp. Bootcamp is actually like a separate partition and shouldn't affect the macOS system - but I'm not 100% sure here. I've always avoided boot camps. : D

      Maybe another reader has a tip on how to solve the matter with your MacBook Pro from 2020. The iMac shouldn't be the problem according to the compatibility list.

  46. If you are interested: a new MacBook Air (Apple Silicon) from 2020 goes well with my iMac 27 “Late 2009 with High Sierra, the display target mode kicks off.
    That's what I call sustainability, the iMac runs better after 11 years than on the first day, ok, thanks to SSD ;-)

    1. Hello Robert! Thanks for this feedback. Definitely interesting! May I ask you what kind of cable you are using for the connection? In the last few weeks there have been numerous people for whom it does not work with MacBooks from 2018/2019/2020.

  47. Walter Stefan Fuchs

    Point 1: THANK YOU very much for the great efforts to offer such a support page
    Point 2: I just can't see the forest for the trees now. I have a Mac mini 2018 (MRTR2D / A). I want to use my iMac 27 “Late 2009 as a monitor. Which cable do I need now?

    Can I use hard drives attached to the iMac with the Mac mini? thanks

    1. Hello Walter Stefan! With pleasure. : D And to 2. What connections does your Mac Mini have? Even the flat USB-C sockets? That would be important to say which cable you need. The iMac Late 2009 should definitely have a mini-DP port on it, if I'm not mistaken.

    2. Walter Stefan Fuchs

      Thanks ... ..Mac Mini has 4x Thunderbolt 3, so USB-C.

      If I'm actually only using the iMac as a monitor ..... can I somehow use the internal iMac hard drives when using the Mac mini as the main computer?

      1. Hello Walter! Unfortunately, no. This is actually just a connection for video. The iMac remains a stand-alone Mac that wants its hard drives to itself. ;-)

  48. Hello Sir Apfelot,
    I hope you can also help me if necessary. I beamed my iMac 21,5″ (late 2013) back to High Sierra and connected it to my newly arrived M3 Mac Mini (Big Sur) using the original Thunderbolt 2 adapter and TB1 cable. Unfortunately, none of the key combinations mentioned in the login window gives access to the "old Mac". The combination cmd+fn+f2 results in only one system tone.
    Do you happen to have any idea / solution?

    1. Hello Christian! You can shut down both devices again. Then boot the Mac Mini and log in and then boot up the iMac and log in. And then try cmd + fn + f2 again. I think you have to be logged in to do this and sometimes it matters in which order you start the devices. The iMac should be the last.

  49. Hello Sir Apfelot
    I have an iMac 27 ″ late 2012 and a Macbook Air 2013 and cannot use the iMac as a screen. I connected both devices with tunderbolt cables and all F2 + cmd or FN key combinations do not work. Both devices shut down again and tried again that doesn't work either. Does anyone have an idea or solution?

    1. Hello Pierre! As a tip I read somewhere that you should not start the iMac until the MacBook Air has started up. Maybe you will try again. Otherwise the cable should be the right one. I don't see what it could be related to.

  50. Hello. I read your article with excitement. With which cables is it possible to connect a Windows laptop (usb-c and hdmi) from an iMac end of 2013 (Mini DisplayPort large) to use the iMac as a monitor? Thanks for the help

    1. Hello Benjamin! Unfortunately there is no cable for this. Unfortunately, you cannot pair the iMac with a Windows computer to use it as a monitor. This only works with selected Apple computers. I'm sorry. :(

  51. Hello
    many thanks for the comments! I have now played through the whole thing in every possible way ... .. unfortunately without success :( Could it be that Big Sur and the new M1 are the problem? I have a 27 Mac from mid-2010 with High Sierra 10.13.6. Should but somehow fit. Thank you very much for your support.

    1. Hello Bernhard! Another reader had recently contacted Apple Support and they told him that Macs from 2020 (still with Intel processors) should not work either. However, there was other feedback from readers who still managed it. I can hardly tell what is right now. But I think Apple won't have a focus on it and will sooner or later remove the feature from the system. Or they have already deleted it. What should work, however, is the solution with Air Display, which I briefly mentioned in the article above.

  52. Hello Jens, many thanks for the prompt reply. I don't think Apple supports it either. you mean airplay? I have already tried. Unfortunately, I have the problem that Airplay is not visible in the menu bar for me. I've tried activating them several times via System/Library/CoreServices/Menu Extras and Displays menus. This only leads to a brief twitch in the menu bar and then disappears again….what the hell. But I can stream via Airplay in iTunes. I then reinstalled High Sierra. Didn't help either... maybe you'll see a solution in the "crystal ball" Thank you for your support!

    1. Hello Bernhard! I meant “Air Display”. This is not Airplay, but an app that can integrate an iPad or another Mac as an additional monitor. You can here read more about it and install the software.

  53. Hi
    I have an iMac late 2013 with OSX 10.11.6 on it. Now I wanted to connect my new Macbook 2020 Intel to this iMac, but all I get is this Apple sound that comes when something goes wrong.
    I connected the two with a Thunderbolt 3 to Thunderbolt 2 adapter and here it continues with a Thunderbolt 2 cable to the iMac.

    I've tried registered and also in the log-in window, with the fn key and without, with the original Apple keyboard and others, but nothing works.

    Does anyone know why this doesn't work?

    Many thanks for your help.

    1. Hello MC! You could try again first booting up your MacBook and then booting up the iMac. Sometimes that helps. Otherwise, you could try another cable. There are users who have reported to me that the Apple cables and adapters did not work. I don't know why that is, but that was the feedback I got.

      1. I just got the following answer in another forum:

        The iMac at the end of 2013 has a Thunderbolt 1 (A) port, which is why a Thunderbolt 2 connection is not possible.

        Have you ever heard of that? Is that actually a MiniDisplay Port even though it has the Thunderbolt symbol next to the slot?

        1. Hello MC! This is new to me that it could be because of it. It may be that they have different TB versions, but actually everything should be backwards compatible. And from what I've heard from a reader, it doesn't even have to be Thunderbolt. The reader had a mini-DP cable and a Thunderbolt to mini-DP adapter. No Thunderbolt protocol will go over it and still it works for him ...

  54. Question about connecting two Macs and many time-consuming attempts:
    Can someone tell me which cables (possibly plus adapters) I have to order in order to be able to use two iMacs together as monitors.
    Mac 1 is main device: runs on Sierra 10.12.6, 27 ″, end of 2013.
    Mac 2 as a second monitor, Sierra, 10.13.6, 21,5 ″, late 2009.
    The attempt via Thunderbolt 2 and keyboard commands cmd and FS 2 failed. An installation via Firewire hard disk mode instead of a startup disk.
    I'm so slowly at the end of my Latin ...
    It would be great if someone had the right tip. Through the whole search I came across this page until today I can say: great page with a lot of news. As a solo entertainer you are usually left out.
    Sound Health!
    Horst Andresen

    1. Hello Horst! Unfortunately, you won't be able to do it with any cable in the world, because your iMac is 21,5 inches and it is the 27 inch model from 2009 that can be used as a monitor. Here's the problem ... not with the cable. :(

    1. Hello Horst! At the top of the article are the models that are compatible with the mode:

      iMac end of 2009 27 "
      iMac mid 2010 27 "
      iMac mid-2011 to mid-2014

      ... unfortunately yours from 2007 falls out ...

  55. Hallo,

    Despite reading the posts, I still don't understand which cable or adapter to use. I have a 21,5 "iMac late 2013. It has two Thunderbolt interfaces on the back. What I can't find out is whether it's thunderbolt 1 or 2. I'll get a Mac mini M1 soon. This of course has a USB-C interface. Whether Gen1 .1 / 2 or Gen2 .1, I don't know. Anyway, I want to connect the Mini to the iMac and use it exclusively as a monitor. Do I now need a USB Gen1 .1 or USB-C Gen2 cable. 1 etc. on thunderbolt 1, or thunderbolt 2? I am very happy about every constructive answer. I'm just older.

    1. Hello Wolli! I hope you get this message here, because I am currently facing an (almost) similar problem. I have an iMac late 2013, but the 27 ″ model and I also want to buy the new MacMini with the M1 chip. Have you been able to successfully pair your iMac and if so, which cables did you use?

      Best regards,
      Philip

  56. Hallo,
    I am now on the verge of despair or I misunderstood the article.
    I use an iMac Retina 5K, 27-inch, 2017 (Thunderbolt 3) to work and would like to connect my iMac 21,5, at the end of 2013 (Thunderbolt 2). I connected both devices with an original Thunderbolt 2 cable and a Thunderbolt adapter to Thunderbolt 2. The older iMac has Mac OS 10.15.7 as the current version and is in the login mask. for my user. Or may there be no user account on this iMac at all? I just can't get a connection as a second monitor, can someone help me

    1. Hello Karol! I don't think the iMac should run anything newer than macOS High Sierra. That was the statement from an Apple support representative. If you want to reinstall an old macOS on the iMac, you have to reboot it and hold down CMD + ALT + R immediately after the restart. Then the macOS with which it was delivered will be installed. And THAT it should actually work. : D

  57. Hello Jens, Your site is worth its weight in gold ;-) Unfortunately, I don't understand a lot about the whole technology and can't quite keep up with the discussions. May I therefore ask you whether and how I can combine the following combination ?:
    iMac (21,5 ″, late 2013) with Catalina 10.15.7 - MacBook Air (M1, 2020) with Big Sur 11.1
    Do I have to update the iMac's operating system to High Sierra 10.12. “downgrade”? Which cables/adapters should I try? Thank you very much, Carol

      1. Thank you very much for your tip. Unfortunately it didn't work for me. So again for the community:
        iMac late 2013, 21,5 ” with High Sierra 10.13.6 and Mac Book Air 13″ (M1,2020) with Big Sur 11.1 worked for me with the following adapters and cables despite different booting, considering the login window and pressing cmd+Fn +F2 and cmd+F2 key combo NOT working:

        1.Apple Thunderbolt 2 cable (2,0 m)
        Thunderbolt 3 to Thunderbolt 2 adapter

        2. USB-C to mini DisplayPort cable
        CABLEDECONN USB-C Type C to Mini DisplayPort / Mini DP

        3. DeLock cable Mini DisplayPort St / St
        JSAUX USB C to Mini DisplayPort adapter

        Nevertheless, thank you very much for this great forum, keep your fingers crossed for the others that it works with their devices!

        1. Hello Caro, have you found a solution in the meantime? I have exactly the same setting and the same problem.
          LG Markus

  58. Hi Jens,

    Your site is really worth gold (has already helped me with a few problems). However, I now have a presumably imminent problem and would like to ask whether there is already experience on this.

    My previous constellation was: 1x iMac 2012 21,5 ″ with macOS 10.15.7 and 1x iMac 2013 21,5 ″ with macOS 10.15.7. I connected the two directly via a Thunderbolt cable (both iMacs still have the Thunderbolt 1 ports).

    Now my 2012 iMac has died a hardware death and this week I'll get a Mac mini 2018 as a replacement, which has Thunderbolt 3 ports and will probably also have macOS 11 (Big Sur) installed.

    My question: can I still use the 2013 iMac with the Thunderbolt 1 connection cable and a TB3-to-TB2 adapter that I still have as a second display in screen synchronization mode for the Mac mini? Or do I need a different adapter or even a different cable? (Or is it not possible at all?)

    Regards
    Jörg

    1. Hello Jörg! Yes, that could work with the adapter and TB cable. But I think you need to downgrade the iMac to macOS High Sierra. To do this, boot the iMac and hold down Shift + Option + Command + R (⇧+⌥+⌘+R). Then it boots into Internet Recovery and installs the system that came with the iMac. That would have to be something older, but the mode for “Use iMac as a display” should work with it. Please let me know if that worked.

  59. Hello and thank you for the extensive contribution.
    I have a MacBook Pro (13 inch, 2020, four Thunderbolt 3 ports) with Catalina 10.15.7 and Intel Iris Plus Graphics 1536 MB graphics card.

    The 27 ″ iMac from the end of 2012 also runs the same Catalina version and has the NVIDIA GeForce GTX 660M 512MB.

    With a USB-C cable, starting from the MacBook, to Thunderbolt - no success.

    Even with a USB-C to HDMI cable - into an HDMI to Thunderbolt adapter - no success.

    Is there now only the € 80 option for the two Apple adapters?

    1. Hello Alex! I think the problem could be that the iMac is only allowed to run under High Sierra at the most. When that is done, the expensive Apple adapters should also work. At least that's what other readers who spoke to Apple Support told me.

  60. Update on my request already made at the beginning of December 2020:

    Imac Mid 2011 (Sierra - meanwhile High Sierra) should act as a display for my MB Pro 2020 (Catalina).
    Despite frequent attempts with the original cable TB - TB and original adapter TB 3 (USB-C) to TB 2 no success until today.
    So much for the past.

    Now my update on my latest experiences (It's getting stranger and stranger)

    I recently bought a second-hand Apple Thunderbolt Display 27. (Because I think it's optically very nice in contrast to today's displays)

    As a display with the original adapter TB 3 (USB-C) to TB 2, the Thunderbolt Display 27 works perfectly as an external screen for my MB Pro 2020. That means that the video signal comes into the display.

    Now came my plan to outsmart the system:

    With a direct connection from TB Display 27 to Imac Mid 2011 (daisy chain and therefore without an adapter from display to Imac), I wanted to use the Imac Mid 2011 as a screen, as originally planned.

    Result - also unfortunately no!
    The video signal continues to go from the MB Pro 2020 to the Thunderbolt Display 27, but unfortunately not to the I Mac Mid 2011.

    But now comes the big a-ha experience.
    Had my daughter's I Mac (End 2012) with me for a few days. I tried the same constellation.
    I Mac End 2012 (with Catalina !! - as main computer) via TB - connection to Thunderbolt Display.27 and then via TB (Daisy Chain) to I Mac Mid 2011.

    See there - works perfectly! Immediately I was able to arrange all three screens!
    In BOTH directions!
    Even if I use the older I Mac Mid 2011 as the main computer and then go to the I Mac End 27 via the TB display 2012, I can use it as a screen, even though Catalina is already running on it. (It is always said that max.High Sierra is suitable for the screen function)

    The following result and question at the same time result for me from this test arrangement:

    It can only be due to the video signal of the MB Pro 2020 or the adapter TB 3 to TB 2!

    Otherwise, why is the video signal from the MB Pro 2020 only transmitted to the Thunderbolt Display 27 and then gets "stuck" there, but the video signal from the I Mac at the end of 2012 is forwarded from the Thunderbolt Display 27 via daisy chain to the I Mac Mid 2011?

    In any case, I'm at the end of my game! - But maybe there is someone in the forum who has an explanation for it.

    Anyway, thanks and LG.

    1. Hi Andreas! The problem with this is that it's not just a normal video signal as I understand it. The MBP sends a "you are now a display" signal to the iMac and this will probably not go through the Thunderbolt display. If you were to connect a normal monitor, there would certainly be a video signal.

      1. Hi Jens,

        sorry, I'm probably standing next to the shoes, but your explanatory assumption is unfortunately incomprehensible to me.
        You mean that the signal “You are now a display” gets stuck in the Thunderbolt display.
        Then why can I loop it through the Thunderbolt display when I connect my daughter's I Mac (late 2012)?
        In your opinion, what difference would there be if I would connect a second Thunderbolt display via daisy chain instead of my I Mac in mid-2011? Does that work then? With the current LG displays that have Apple approval (with Thunderbolt 3 connection), it should work in any case.
        LG Andreas

        1. Hi Andreas! I'm not a techie and I'm not familiar with this particular transfer of information that Apple uses here for the "iMac-is-Display" mode. The only way I understood it was that when the iMac is daisy chained behind the Thunderbolt display, it no longer displays an image. And the only reason I can think of for this is that this particular signal is "stuck" in the TB display. A second TB display would work in my opinion.

  61. Hello Jens, I greet you!

    I've been following this post for days because I'm about to buy a new MacMini 2020 and use my iMac (Late 2013) as a monitor. Now I came up with a strange idea, but since I'm not an expert I am probably completely wrong. But …

    ... wouldn't it also be possible to connect the iMac to the HDMI 2.0 input of the new MacMini using a MiniDisplay cable and an HDMI adapter (optionally also a MiniDisplay cable - HDMI)?

    1. Hello Phillip! So in terms of the connectors it will probably work, but unfortunately I can't say whether the right signal will come across. You'd have to try that. There are so many imponderables with this iMac-as-monitor thing that I cannot make a definitive statement about it. But, if you try it, I would be very interested in the result! The iMac then has to run on High Sierra or lower.

      1. Greetings Jens and thank you in advance for your quick reply! As soon as my MacMini has arrived, I will of course report to the Apple community. Since I'm definitely already doing some research, I have a question about the MiniDisplay Port. For the adapter you suggest at the top ( JSAUX USB C to Mini DisplayPort Adapter ), the description on Amazon says: "Please note that this C to Mini DP Adapter is NOT compatible with monitors or devices with a Thunderbolt 2 port." Now I'm confused again.

        1) Does that mean that I definitely have to use a MiniDisplayPort CABLE or

        2) that this adapter actually ONLY works with products that also have an original MiniDisplayPort? (My iMac has Thunderbolt 1)

        3) Thunderbolt 1 uses the same connector as MiniDisplayPort or not? Doesn't it matter if I use a MiniDisplayPort cable or a Thunderbolt (1 or 2) cable?

        Has anyone here already paired a Thunderbolt 1 iMac with the new MacMini? I read all the comments again. It's a mess, but the cables from Apple are so expensive * aaaaarrgh *

        Kind regards and Jens, you are doing a great job here, keep it up!

        1. Hello Phillip! Yes, the cables from Apple are very expensive and unfortunately not the best choice in this case. I've had readers where the Apple Cable + Apple Adapter didn't work, but the JSAUX Adapter did. But to your questions: 1. I don't think you can use a simple cable because the signal for the target display mode is "more" than just the pure video signal. But unfortunately I'm just reading the crystal ball here. 2. The JSAUX adapter is USB C and plugs into a USB-C port, which (to my knowledge) is Thunderbolt 3. But maybe there are also devices with TB 2 in the form of USB C. It should go there too. 3. You have to test that. In this case, I would rather try a Thunderbolt cable, since more is transmitted here than with a mini-DP cable.

          I know there's a lot of "maybe" and "actually" on this one. Unfortunately, that's the case with this connection... I keep getting very different feedback and can't see any real pattern. With the JSAUX adapter, I got the message that it works with a current Mac.

  62. Michael Scherer

    Hi all,

    Since I didn't want to throw my iMac 27 ″ in the bin in 2010, the topic was of course very interesting for me. Therefore, I would like to give you a brief feedback on what works for me:

    Mac Mini Late 2018 I5

    Monitor 1:
    Imac 27” 2010 about JSAUX USB C to Mini DisplayPort adapter and Delock Cable DisplayPort mini male / male in target display mode

    Monitor 2:
    Philips 272B8QJEB / 00 68,58 cm (27 inch) monitor via HDMI

    Both in the resolution 2560 x 1440, I'm super happy with the solution, the iMac now serves as a monitor and hard drive (in the network).

    Maybe it will help some, greetings and, despite the current situation, nice Easter days.

    Regards
    Michael

    1. Hi Michael! Thanks for your report. I'm sure this will help some readers choose. I have also linked your product names directly - I hope for the right products. LG, Jens

  63. Hi Jens,

    I have an old iMac early 2008 that was put on Linux Mint.

    Could I connect my Windows 10 laptop to it and use the iMac 08 as a screen?

    I saw that it wasn't listed in the 'Requirements', I was just wondering if it might be worth a try and asking for your opinion.

    Best regards,

  64. Hi all,

    I have a follow-up question about the update from 18.03.2021/XNUMX/XNUMX, with which you, as a layperson, might be able to kindly help me.

    I would like to use my iMac (end of 2009 27 inch) as an external monitor for my Lenovo Thinkpad X1 Yoga. Since the Lenovo laptop is my work computer, only a connection via a connection cable (and no network transmission or similar) is possible.
    In the update of March 18.03.2021, XNUMX you write that a transfer should be possible in principle, according to the procedure you described.
    Unfortunately nothing happens when I connect a mini-dp (iMac) / Thunderbolt C (Lenovo) and click cmd + F2.
    Does anyone have any idea why this might be? I have also tried other “cable combinations”, such as mini-dp to HDMI or VGA, to no avail.
    Is there possibly a matter of attitude, for example with the resolution

    I would be very grateful for any tips!

    Regards

    1. Hello jim Unfortunately, I am overwhelmed with Windows PCs because I don't know which ports are transmitting what. What system is installed on your iMac? A maximum of macOS High Sierra can run here.

      1. Hi Jens,

        I have OS X El Captain installed. In my understanding, that should be the operating system before Sierra and thus also High Sierra, so that it won't be the show stopper here?

        My Windows computer has a Thunderbolt C connection, so the basic technical requirements should be met, which in turn means that the transmission should work. So it would only be a matter of attitude, right?

        Regards
        J

        1. In theory you are right about the statements, but the problem is that there is not much to adjust. :(
          But it shouldn't be due to macOS. I can't say anything about the Windows computer ...

  65. Hi Jens,
    I found your instructions here over a year ago and at the time I established a super stable connection between my old iMac and my MacBook Air, which enabled me to use the old iMac as a monitor. Now I've bought a new MacBook Pro (2017), which of course only has USB-3 ports. So I bought an adapter for my old Thunderburd cable so that I can continue to use the construction. So far so well that worked for almost a month. But now there is a problem: My iMac suddenly no longer wants to recognize the MacBook. Switching off, restarting, reconnecting the cable, etc. all does not work. If you wait a few days (!), The first connection works again, but after a break the old problem comes back. The cables are totally functional and also originals from Apple. Maybe you have an idea what else I could do? But renew the cable again? I also looked for a USB-3 to Thunderbird cable to connect directly without an adapter, but I couldn't find that anywhere ... Thanks for all the ideas!

    1. Hello Robert! Hmmm ... that sounds strange. How could a break have such an effect ??? I can't explain it to myself technically at all. As a test, you could again create a new user and start from this and try to see whether a connection is established. Or did you maybe change something in the time when it stopped working? New software installed or something? The iMac should still have a maximum of High Sierra.
      Otherwise you could try the other cable-adapter combination again, which also works with some: JSAUX USB C to Mini DisplayPort adapter and Delock Cable DisplayPort mini male / male. Maybe it works with that? Otherwise I'll really run out of ideas ... :(

  66. Hallo,

    I've read so much that I don't even know what I need. ;-))

    Maybe one of you can help me, would be very grateful.

    My setup:

    Macbook Pro 13 ′ at the beginning of 2011 is to be connected to an Imac at the end of 2012.

    Is that possible and if so, which cable do I need. ;-))

    Thank you

  67. Hi Jens,

    I was so excited when I read your post !! My old iMac still has uses. So I immediately ordered cables and adapters from Amazon. Today it arrives and the result is unfortunately ... nothing happens !!

    Here with setup:

    MacBook Pro 13 ″ M1 2020
    iMac 27 ″ in mid-2011

    Cable Delock cable Mini DisplayPort M / M black but only 1 meter long
    Adapter JSAUX USB C to Mini DisplayPort adapter

    I had macOS 10.13 (High Sierra) on the iMac. After 2 keyboards (Apple Keyboard Bluetooth and Apple Keyboard with cable) did not work with this macOS, I reset the iMac to its original macOS, so it is now macOS 10.7.5 (Lion) on the iMac. And yet it doesn't work.

    It's not the problem with the MacBook Pro with the M1 chip or Big Sur?!?!

    I hope you can help!

    Greetings from Hamburg
    Nina

    1. Hello Nina! Yes, unfortunately you cannot predict the result. I have no other reader who recommended the cable and adapter to me because that is exactly what they do. I'm sorry it didn't work out for you. If I remember correctly, he has a Mac Mini M1. So actually Big Sur and M1 may not be the problem. I'm starting to get the feeling that it is pure coincidence whether it works with a combination of devices or not. I know, unfortunately that doesn't help you now, but I can't say any more ...: /

  68. Hallo,
    thanks for the great article!
    I have a question, too:
    I want to use an iMac (late 2012) as an external monitor for a new iMac (with Thunderbolt3). Is that possible and which is the right cable?
    Thanks in advance

  69. Dear Jens, thank you very much for your great article!

    Since the last time I just ordered some kind of cable and unfortunately it didn't work, I prefer to ask again this time:
    I would like one
    - MacBook Air (Retina, 13-inch, 2020) with macOS Big Sur with one
    - iMac (27 ″, end of 2013) with macOS Catalina
    . connect
    I would then install macOS High Sierra on the iMac.
    Could you help me which cables to buy?

    Thank you for your help!!

  70. Hi Jens,
    The problem is also for me - on the one hand iMac 27 ″ late 2009 with High Sierra and on the other hand my MacBook Pro from 2016 with Big Sur and the question can both devices be connected? On the Apple support page (https://support.apple.com/de-de/HT204592) says: “The other Mac you want to connect to must be from 2019 or earlier. In addition, macOS Catalina or older should be installed on it. LG Ole

    1. Hello Ole! Unfortunately, I don't have any experience to offer, but I've heard from other readers that Apple Support even says something about macOS High Sierra at most. I think Big Sur falls flat with it when they point it out. But maybe someone else has an experience report ready.

      1. I was able to realize the following connections. My iMac is from 2011 (macOS High Sierra). I can use a MBP 13 ″ from 2012 with MacOS Catalina via Thunderbolt. A 2014 MBA with BigSur was also recognized. The iMac reliably fulfilled the function of the second screen.

        Sincerely, Mic

  71. Maybe I skipped it, I'm interested in whether it will still work with the new M1 MacBooks? So for example iMac from 2011 and new MB-Air with M1?

    Sincerely, Mic

    1. Hello Mic! Unfortunately, I cannot make a binding statement on this. But I think that a reader with the Mac Mini M1 wrote to me that it still works for him.

  72. Moin moin Jens, first of all I would like to thank you for the great article! I also like other of your articles very much and cannot be found anywhere else.

    I have an iMac from mid-2011 and would like to use it as a monitor for a Windows PC with an HDMI output; In other words, HDMI (male) to Thunderbolt (female / better: male, since an additional Thunderbolt cable is very expensive). Unfortunately, I only ever find variants to Mini Displayport:
    FOINNEX Hdmi to Mini DisplayPort Adapter, Gold-Plated 1080P Active HDMI to Mini dp Video Converter Male to Female for Apple Cinema Display (24/27/30 inch), iMac 2009/2010, Dell MDP Monitor, Projector https://smile.amazon.de/dp/B086MM1VKP/ref=cm_sw_r_cp_api_glt_i_PE1WRSRHEPM1BGP0ZYC3?_encoding=UTF8&psc=1&tag=sirapfelot-21

    Can you or the community help me? I think it would be a shame to give the iMac away ...

    Kind regards
    Timo

      1. Hi Jens,

        I want my iMac (21.5 inches, mid 2011); Use OS X El Capitan as a monitor for a Windows tablet with HDMI and / or DisplayPort connection. I don't care which output I use on the Windows tablet.

        The iMac has a Thunderbolt and no mini display port. I don't know if this is crucial for my project. On the apple homepage I only read that Thunderbolt and Thunderbolt 2 are not the same as Mini DisplayPort.

        I am now irritated because the description of the cable you linked (concerns your answer to Timo of June 13, 2021 at 14:37 p.m.) says:

        “Important Notes While Using

        1:If you use from displayport computers to your mini displayport monitors,only if your monitor is mini displayport can work,if your monitor is thunderbolt 1 and 2 port,it can not work.”

        If I understand correctly, my iMac, which only has a thunderbolt port, shouldn't work as a monitor after all, right?
        Or does that just mean that I can't transfer a picture from the iMac with the Thunderbolt port to the Windows tablet? The latter wouldn't matter.

        Alternatively, I wonder if there isn't just an HDMI to Thundebolt cable? Or what kind of connection would you advise me to do?

        Thank you for your help and best regards
        Klaus

        1. Hello Klaus! Thanks for your comment. Let's clarify the simple thing first: I don't have an iMac and can't test whether an HDMI to TB 1 cable would do it. But I can imagine that we need mini-DP so that the iMac gets the right signal, otherwise you might have read the idea more often somewhere.
          What I can definitely say: Your iMac 21,5 inch (mid 2011) definitely has a Thunderbolt 1 port. I just got that at MacTracker looked up. And my cable recommendation is based on feedback from readers who worked. I can't check it out myself. But there are always people who can't get the iMac to display a picture. If you want to be on the safe side, I would give you AirServer as this is a more tolerant solution to using the iMac as a monitor.

  73. Hi Jens,
    Thank you for such an informative article. I also have a question about the connecting cables. I would like to connect my iMac 27 to a new MacBook Pro with M2011 in mid-1 and use the iMac as a monitor.
    -What kind of connection cable do I need then?
    -And is it still possible to use the iMac despite a defective hard drive? However, it continues to work via an external hard drive with High Sierra.

    LG
    Anna

    1. Hello Anna! Yes, you can still use iMac if you boot it with an external hard drive. It doesn't matter - the main thing is that it's still running. Whether the thing with the M1 MBP works, I can not say exactly. A reader said it would still work for him, but a few others have written that it doesn't work. Ultimately you will have to test it. With your constellation you need the two products that I have listed under the paragraph “Update 12.12.2020/XNUMX/XNUMX: Mini-DP to USB-C solution” linked. I would be super happy if you could give me feedback if it works for you. A few experiences would help the article here - and certainly many other readers. Thank you!

      1. Hi Jens,
        Thank you very much for your quick response. I don't want to give up the hope that it will work with M1 :) Of course I will report whether it works for me, I just need time :)

        Thanks again

  74. Unfortunately it doesn't work on my 27 inch in the middle of 2011 with M1 minimac and the Ruipoo USB C to Mini DisplayPort cable!

    would have been great, my desk is too small with a third monitor because the Imac has to stay ... Not all software runs on the M3 Minimac

      1. Yes there is 10.12.6 on it ... sierra !!! it would be great if it worked ... means one less monitor on the desk ...

  75. iMAc 2012 as a screen, MacBook Pro 2015 as a computer. Connected via Thunderbolt. Runs great during the day. I only have to press cmd + F3 again when hibernation becomes active. That doesn't work anymore because the iMac doesn't recognize the keyboard (it is connected to the MACBook Pro). Activate as a button on the iMac, switch with cmd + F3, then disconnect the keyboard and connect it to the MacBook Pro. Is there a solution for this?

    1. I think if it's not a typo, you're just using the wrong F-key. For me it's cmd & F2. I have now consciously tried it in the login window, from the logged in computer, and it only works for me with the two buttons.

      Sincerely, Mic

  76. Hello Jens, I too am faced with the challenge of using my iMac (end of 2015) as a display for a Macbook Pro (2020). I connected both with a Thunderbolt adapter + Thunderbolt cable. Unfortunately nothing happens with cmd + F2 .. maybe the device versions simply cannot be combined? I'm slowly no longer seeing through ..

    1. Hello Sarah! The MacBook Pro is not a problem, but unfortunately your iMac is not compatible and does not have a Target Display Mode. As stated above in the list of supported models: “iMac Mid 2011 to Mid 2014”. After that, no more iMac can be used as an external monitor. sorry :(

        1. I recommend AirServer. I've been using this solution for a few months now and I'm completely satisfied with it. You can download the AirServer software online and try it out for a few days. After that, a one-off payment is necessary, which is still cheaper than an Apple cable 😉

          1. Hello MC! Thank you for your complement. That's a good idea for anyone who can't take the "Apple Way". Does AirServer have a noticeable latency when moving the mouse over the iMac?

          2. No, 95% of the time it is as if the mouse were directly connected to the imac. it seldom happens that the connection is stuck for a few seconds, until it then continues smoothly.

      1. Hi Jens,

        I had already followed this topic at an earlier point in time and, thanks to your help, I managed to find a solution for my MBP / iMac 2011. A question that now arises is this use also for M1 devices, so in my case for an MBA with M1?

        Is this “Air Server” maybe a solution. Nothing seems to work with the hardware. Does the group of “Apfelot disciples” have any experiences with the topic of continued use of old iMacs as 2 monitors with M1 devices?

        Kind regards, Mic

        1. Hello Mic! So if I were faced with the choice, I would currently rely on AirServer. I've heard from various readers that M1 Macs can and can't. This whole story seems so random that I would favor AirServer here. This definitely works with the M1, M2 and other future Macs, as the software is maintained. However, I have not yet fully figured out whether AirServer only mirrors the screen content of the Macbook or whether you can also say that the controlled iMac is an extension (that is, it shows its own content).

  77. Hello, thank you very much for this article.

    I'm a little confused about the iMac and MacBook Pro connection.
    My setup (i.e. what I would like to have)

    Source / main device:

    13 ″ MacBook Pro Retina (Late 2012) - has two Thunderbolt ports - no MiniDisplay ports

    Second monitor (ideally): My Late 2009 27 ″ iMac (Mini Display Port) - No Thunderbolt

    My question: How do I connect the iMac (which has a mini display port but no Thunderbolt port) to the MacBook Pro which ONLY has Thunderbolt (no display port) to use the iMac as a second monitor?

    Is there a trick for that? Do I need a mini display cable (into the iMac) and then a MiniDispaly to Thunderbolt adapter for the other end into the MacBook Pro?

    Ie source - end A (iMac) - MiniDisplay Port and plug the other end of the cable into the MacBook Pro (Thunderbolt) with a MiniDisplay-Thunderbolt adapter? Is that how it works?

    TL DR: iMac has MiniDisplay, but no Thunderbolt (my ideal screen)
    MacBook Pro - main unit - has two Thunderbolt ports - no mini display

    I am grateful for any help and guidance. I couldn't find any answers to this online>

    Thank you

    1. Hello Aly! Apple has an adapter from Displayport (Mini DP) to Thunderbolt 2. Either you do it with it or with the adapter cable that I have also linked above. The cable offers USB C (connection like Thunderbolt) on one side and Mini DP on the other. I hope you can handle it.

  78. Hi Jens,
    great article !!!

    I want to use my old 2013 imac (A1418) as a desktop with a Surface 3 pro.
    I've tried different cables and connections but nothing seems to work for me: (Mini DP to Mini DP; Mini DP to Thunderbolt 2 and Thunderbolt 2 to Thunderbolt 2

    Do you have another tip? Because the keyboard shortcuts above didn't work.
    VG,
    Daniel

    1. Hi Daniel! I can't say why it is, but I would just give the way AirServer choose ... it's also available for Windows and can send the image to an iMac if I understand it correctly.

  79. Hello, Jens!
    I've been using an iMac in Target Display Mode for years, but now need to replace that device. My question: was an iMac 21,5 Late 2015 (without Retina display) ever tested - or was the information from Apple trusted?
    I know this topic has been dealt with here many times, but my current configuration should not work either (the "second monitor" runs under macOS Mojave).
    As an alternative, I am currently testing AirServer according to the above recommendation.
    LG, Martin

    1. Hello Martin! I haven't tested it myself, but I think you can be very confident that it won't work. There is simply a piece of hardware missing that makes the target display mode possible. And I've already had a lot of people here who didn't work out, and who later found out that they have too new an iMac model. I'd rather pan to AirServer ... that seems to work reliably with any iMac.

  80. Hello, Jens! I haven't bothered about this topic for a long time and my eyes have adapted to the small monitor of my MacBook ;-) nevertheless I do not admit that I can still use my IMac as a monitor. I have an iMac 21,5 inch, in the middle of 2011 and would like to pair it with my new macbook? Can that be done via AirServer? And where do I get something from or do I have to pay attention to something specific? LG Mel

    1. Hello Mel! I haven't tried AirServer myself, but if I understand correctly, it's just software that you install. You can find the Mac download here: https://www.airserver.com/Buy/Mac
      There is also a 30 day trial period ... so you have enough time to see if this is the right solution for you before you have to insert money.

  81. I have an iMac 27 ″ from the middle of 2010.
    Basically it works, but I have now bought a mac mini m1, and would like to know whether I can combine the two with each other by using the imac as a monitor, and how exactly (which cables do I need exactly for this) .

    1. Hi SKipper! Good question. I have not yet received any feedback from other readers as to whether this will work. I mean, a reader once had a success message, but nothing more came back.

      1. i'm thinking - because that didn't work out, and because i have to wait about 4 weeks because of the delivery problems for the new macbook - whether a (large) ipad could serve as a monitor for the mini ...⁇ 🤔
        if that were possible, however, it would have to be activated when the mini was started ...
        …any ideas?