Instructions: Downgrade from macOS Catalina to macOS Mojave

Did you have too many problems, errors and failures after upgrading your Apple Mac to macOS 10.15? Then it is worth downgrading from macOS Catalina to macOS Mojave. You can find the instructions here so that nothing goes wrong. However, if you have a bootable backup of your Mojave or High Sierra system with you before the Catalina upgrade Carbon Copy Cloner, superduper! or SmartBackup have made, this post is not for you. Then you can simply upload this backup to your Mac and use the Apple computer as before without long instructions;)

Tip: With the app "AnyMacOS"You can easily create a bootable USB stick and the app will even download the appropriate macOS image (from macOS High Sierra) for you.

Here you can find the instructions for the macOS downgrade from 10.15 Catalina to 10.14 Mojave.

Here you can find the instructions for the macOS downgrade from 10.15 Catalina to 10.14 Mojave.

Update January 17.01.2020th, XNUMX: New Macs do not allow a downgrade

I got an interesting tip from a reader who has a new 16-inch MacBook Pro. He tried to downgrade it to Mojave and also noticed the matter with the T2 chip, but the Mac keeps throwing an error message. Apple Support then confirmed that new Macs that were already shipped with macOS Catalina AND were only released after Catalina was released can no longer be downgraded to Mojave. But if you are currently buying an iMac model from 2019 that was available BEFORE Catalina, the downgrade should work. With the MBP 16-inch there is no way to "drive" with Mojave.

First of all: important step for newer Mac models with T2 chip!

If you are using a MacBook Pro, MacBook Air or Mac mini from 2018 or 2019, you will need an extra step when downgrading from Catalina to Mojave. Because inside is the T2 security chip, which makes it necessary that you allow a system to be booted from external data carriers before (!) The downgrade. If you are not sure whether your Mac, iMac or MacBook has a T2 chip, look in the system or at Apple in the device details. If available, you proceed as follows:

  1. Turns the Mac off and then back on or off. restart it
  2. Stop right after turning it on cmd + R (or command + R or ⌘ + R) pressed
  3. Release after booting; now you are in Recovery Mode / Recovery mode arrived (you can also recognize it by the fact that the window "macOS utilities" is displayed)
  4. Click on the item in the menu bar Utilities and then choose Startup security utility (first point) and give your Administrator login a
  5. Activate the option "Allow starting from external media" below
  6. Activated in the upper paragraph "Medium security"
If your Mac from 2018 or 2019 has a T2 Security Chip, you must first specify that the computer can also be booted from external sources. Image source:

If your Mac from 2018 or 2019 has a T2 Security Chip, you must first specify that the computer can also be booted from external sources. Image source: / Update 9.12.2019: A reader pointed out to me that you also have to select "Medium Security" above so that an older system (such as macOS Mojave in this case) can be installed.

Step 1: Back up the Mac

Since the downgrade process described below will completely remove all your data, files, programs, emails, music, photos, etc. from the hard drive, you have to make a backup now at the latest. It is up to you whether you push everything manually to an external hard drive or use one of the backup programs mentioned above. It is important that nothing is lost for you and that you can transfer everything to the Mojave system that is available after the downgrade. Alternatively, you can also use cloud storage to and from which you can copy your data. The only important thing is that everything else is definitely deleted after the downgrade!

Step 2: Create a bootable stick / hard drive with macOS 10.14 Mojave

The best way to create a bootable USB stick with macOS Mojave or an SSD with the macOS installer of the 10.14 version is to use it the instructions linked here. You will not only find that in it Port-Command for the procedure but also the app alternatives Install Disk Creator and DiskMakerXwith which you can create the boot stick or the bootable hard drive using a program with a user interface. You can get the Mojave installer, which you also need for this step, here: 

Step 3: delete macOS 10.15 Catalina

Before you can reinstall Mojave, you have to delete Catalina from your Apple Mac. As a reminder: Make sure beforehand that you can boot from an external medium later and that your data is backed up. Also create the boot medium beforehand according to the instructions linked above. All done? Then it continues with these sub-steps:

  1. Make sure the Mac connected to the internet is (WLAN or Ethernet LAN)
  2. Turns on the Apple computer or restart it
  3. Stop right after turning it on cmd + R (or command + R or ⌘ + R) pressed
  4. Release after booting; now you are in Recovery Mode / Recovery mode arrived (you can also recognize it by the fact that the window "macOS utilities" is displayed)
  5. Select the point in the "macOS Utilities" window Disk Utility and click on the "Continue" button
  6. Selects the hard drive, from which your system is started, and click on the "Delete" button in the toolbar above the selection
  7. Give one Namur for the volume to be erased / formatted
  8. If you want to prepare your hard drive for deleting or formatting for an older operating system (up to 10.12 Sierra), then choose the file system HFS + (it may be that in the selection "Format" only "Mac OS Extended (upper / lower case, Journaled) "appears, but that is the right choice); if you want to install a newer one (from 10.13 High Sierra), choose APFS off (is no APFS displayed? Here's the solution!)
  9. If the "Format" menu can be used, select the GUID partition table (or something like that, the main thing is GUID)
  10. Click on the "Delete" button

Step 4: reinstall macOS Mojave

So if you have decided on macOS 10.14 Mojave as a new installation, you should have selected APFS as the file system when formatting the hard disk. Before I get to the installation instructions, here is a note for everyone whose Mac came with Mojave as the factory operating system: When you turn it on, you just need to press Shift + Alt + Command + R to reinstall Mojave. Thanks to Shift + Option + cmd + R (alternative names), the factory macOS is downloaded and installed again. If your Mac is older than Mojave, here are the instructions for installing it:

  1. To be on the safe side, double-check that a Internet connection consists
  2. Now close your Mojave Boot stick or the boot hard drive with Mojave Installer
  3. Restart or restart your Mac via the Apple menu. turns it on
  4. Hold the option or alt key pressed
  5. Now you can Select start medium
  6. Choose from the list your stick or your hard drive
  7. Now the Installation process from macOS Mojave
  8. Click on "Next" or others Confirmationsthat are needed
  9. Let that Complete the installation process (cmd + L shows the progress and remaining time)
  10. Enjoy a fresh Mac;)

Step 5: Re-equip Apple Mac or install Time Machine Backup

If you have an earlier Time Machine backup from Mojave (not Catalina!), You should upload it now to apply your favorite settings directly. Alternatively, you have to set everything up again by hand. In addition, you can then copy your previously saved files, programs, photos, music, etc. back to the hard drive. For the mentioned Time Machine Backup you proceed as follows:

  1. Again sets the Internet connection for sure
  2. Select the again in the apple menu restart from
  3. Now stop again cmd + R to get into recovery mode
  4. Here you can find the first point in the “macOS Utilities” window Restore from Time Machine backup choose…
  5. ... and then the "Continue" button click
  6. Subsequently agrees to the information displayed
  7. Then select the Backup source from
  8. Continue and then choose the latest macOS Mojave backup from
  9. Click again on "Continue" or "Next"
  10. Wait for the process to complete and then use your restored Mojave system

Source: iMore

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  1. Great guide. But maybe two things should be mentioned:
    1. the whole process of the downgrade takes some time, many hours more than the quick click on the update ;-)
    2. Without an existing backup at a time before the update, the project is extremely time-consuming - it is possible to manually extract even the photo and iTunes data from a Catalina backup, but the albums and playlists are then lost. Without a Mojave backup, there is also no chance of restoring older or local mailboxes

    • sir appleot says:

      Hello Thomas! Thank you for your feedback signal. Do you know if you can use the Mojave Migration Assistant to transfer data from a Catalina installation? That would make the downgrade a lot easier, but since I haven't installed Catalina yet, I can't try it out. Maybe someone has some information about it or can test it?

  2. Manual says:

    Updates are always easy. Downgrades are an art;)

  3. Uwe D says:

    Great instructions, but I have one more note: in principle, you can skip step 3 and do it together with step 4.

    - connect the boot stick
    - start with old
    - select the stick as the start medium
    - Select Disk Utility in the macOS Utilities window
    - Select and format the hard disk
    - Quit disk utility
    - in "macOS Utilities" select "Reinstall OS X"
    - Start installation

    Best regards, Uwe

  4. Mike says:

    Hello everyone, the day before yesterday I installed Catalina on my iMac Late 2012. Programs are running but I have a problem signing into iCloud. First came the message that I should complete the registration of the iCloud, then the two factor code should be entered on the iPhone. But the code never arrived on the iPhone. I then generated a code on the iPhone, but it was considered invalid. Then I read on the Internet that I should log out of iCloud and then log back in again. And that's exactly what doesn't work. I enter my Apple ID and password and the Mac just loads without going any further. The Apple hotline couldn't help me either. Now the question is, should one dare to downgrade? Sounds like a lot of work to me. I still have a time machine backup from Mojava.

    • sir appleot says:

      Hi Mike! If you've already tried everything else, like restarting, etc., all you have to do is downgrade or wait for a bug fix. If you are also dependent on using the iCloud, importing the backup is all the more urgent. Ultimately, however, you have to decide whether you want to do it or not. If you made a mistake, my tips would have been to restart or turn iCloud off and on. If both of these do not help or work, unfortunately I don't have any advice.

  5. Mike says:

    Hello Sir Apfelot. I've tried a lot now. Restart, start in safe mode, etc. I have just logged off the iMac from "Find my iPhone" (or whatever it's called recently). I was briefly hoping that I should type in the two-factor password, which this time also appeared on the iPhone, but then it continues. Maybe I'll wait for the next buckfix. But apparently nobody else has the problem, at least I can't find anything on Google.

    • sir appleot says:

      Too bad ... would have been nice if we could have solved it, but currently it looks like Apple has to deliver something so that you can get further. :-(

      • Mike says:

        Hi, iCloud is now running on the iMac. So far so good. Now pinch it on my iPhone and iPad. I am now supposed to constantly update my Apple ID settings, which I do. Only after a minute does the same request come back. The problem with this is now that my Homekit devices can no longer be operated because the iCloud keychain should be activated. I don't get the switch activated, it jumps back to "off" immediately. I'll contact Apple Support later.

        • sir appleot says:

          Hi mike! Have you ever restarted all your devices? With the iPad and iPhone I would also try a reset (with an encrypted backup). It doesn't take forever and usually solves a number of problems ...

          • Mike says:

            Hi Sir Apfelot, I contacted Apple Support. The solution is as follows: You first have to log out of "Wo ist" (formerly find my iPhone), then log out of iCloud. Now press the following combination: Volume key, volume key and then hold the key down for approx. 10 seconds until the apple appears on the screen. The iPad / iPhone reboots. It helped with my iPad. The iCloud keychain is reactivated and Homekit or the Home app are working again. Unfortunately, that didn't quite work out with the iPhone. The iCloud keychain is now also activated, but my Homekit devices are missing from the Home app. For example, if I want to add my Eve thermometer, I get the error message that it has already been added. The Hue lamps are also missing. When I open the Hue app, the lamps can be controlled normally via the iPhone. It is to despair.

          • sir appleot says:

            Hi Mike! Ok, at least half a success. Maybe the iPhone will adjust itself again when it is reset. That is again "harder" than rebooting.

  6. Opi madness says:

    What if I have a brand new iMac with Catalina installed, but I want to install Mojave due to program incompatibilities (Lightroom!)? I have a TimeMachine backup of a MacBook pro and also a completely new iMac with Mojave. Many greetings Opi-Wahn

    • sir appleot says:

      Hello grandpa madness! The best thing to do is to create a bootable USB stick with Mojave. You can get Mojave itself via the link in this article here, And here you can read how to make the bootable USB stick. Then you boot from the stick, flatten the disk in the new Mac and install Mojave on it.

  7. Mike says:

    So, HomeKit works again. Unfortunately I had to delete my room and re-integrate the devices. With five devices this is still manageable. So I'll wait for the next big updates.

  8. Meini says:

    Hello Sir Apfelot

    Since the Catalina update, I can't sync purchased songs / music videos to my iPod nano.
    What can I do ? if there is anything.

    • sir appleot says:

      Hello Meini! What's wrong? ITunes no longer exists, but when you plug in iPod nano, it should appear as a device in the Finder window. Then you click on it and the synchronization dialog should appear.

  9. jeraro says:

    Hello everyone involved,
    thanks for the help in this block!
    I installed Catalina and it was a mess, but thanks to the tip from "Sir Apfelot" (install Catalina twice in a row) the Mac is running again.
    I now have a strange appearance on my iMac: "One" FusionDrive is installed, but several are displayed:
    If I open: About this Mac, 3 HDD are displayed under Hard disks. And under hardware hard disks even 4 hard disks with a total capacity of 4TB. But there are no green men walking around my house!
    How do I get this back in order?
    iMac 13.2, memory 32GB,
    Model name: iMac
    Model identification: iMac13,2
    I would be very grateful for help!

    • sir appleot says:

      Hello Jeraro! You might see 4 "Volumes" in Disk Utility, but there are only 3 disks. This is probably because you also have a partition or an APFS volume on a hard drive. Normally there shouldn't be a difference. One more tip: You copied the serial number of your Mac into your comment. You should never do that. "Fake iMacs" that do not exist on eBay are then often sold with such numbers. The vendors steal the serial number from forums or something from somewhere and then pretend they have the Mac. The buyer then checks the hardware equipment and warranty with the number and you think the other person actually has the Mac. LG! Jens

  10. Ruby says:

    Now that I have Catalina on my Mac Book I can apparently buy a new scanner! I have an Epson Wf3620 and I have run out of time and energy.

  11. Sven8888 says:

    Hello, thanks for the very detailed description.
    Unfortunately, I already fail to load Mojave from the store.
    The system settings always open and I get the message that I have downloaded the latest update. The download does not start.
    How do you get around this?

    • sir appleot says:

      Hello Sven! So the normal procedure is to go to the Apple Support page:
      Then scroll down and click "Download macOS Mojave from the App Store". The link sends you to the software update looking for Mojave. The "Download" option should appear here. Is it at this point where it breaks off for you? If so, take a look in your Applications folder to see if the Mojave installer is already there. Otherwise I don't know what it could be related to.

      • Sven8888 says:

        Thanks for the feedback
        The Mojave installer is not in the programs. But even after further attempts, he keeps pointing out that the Mac is up to date with macOS Catalina and probably refuses to load an older version.

        Then I will probably have to reset to the delivery state and then try to update from Mavericks to Mojave.

  12. Thomas says:

    I immediately made the jump back from Catalina to El Capitan when nothing worked after the update. The new formatting of the hard drive prevented that I could import the backup directly from the Time Machine. Unfortunately I couldn't get a copy of El Capitan to create a boot medium. After some research I found out that the Time Machine from 10.7 on is also suitable for booting. That probably saved me hours of creating a boot medium and it worked perfectly.
    Regarding step 3: there was no way to select HFS for the formed plate. I was only able to do that when I booted my Time Machine. That’s also called "OS X Extended (Journaled)".

    • sir appleot says:

      Hello Thomas! Thanks for your comment. I didn't even know about booting the Time Machine. : D You always learn something new ... ;-)

  13. thinkup says:

    I have the new Macbook Pro 16 inch. It comes with Catalina and I gave Apple direct support for 2 hours. It just doesn't work, in the end he always downloads the current Catalina from the WiFi.

    Apparently you can only dowgrade a Mac on Mojave if Mojave or lower was installed as the "startup operating system" on the Mac.

    Does anyone have any idea how he came up with Mojave with the current devices?

    • sir appleot says:

      An interesting idea. : D I would try it with an external hard drive. Format it on APFS and then load the Mojave as an installer and try to install it on the external disk. If he refuses, then there really seems to be something to what the Apple people are saying.

  14. M. Rufini says:

    It depends on the Macbook Pro

    My attempt by means of Paralles a Mojave to my Catalina on a 16 inch MBP
    installing it resulted in a reduced screen and the exclusion of all 32 bit programs.

    • thinkup says:

      A MACOS that can do APFS, I was able to format the SSD in APFS. It worked. But then to create the "external boot stick / SSD". Then the error message "APFS disks may be not used as bootable install media. An error occurred errasing the disk."

      • sir appleot says:

        Ah ok. We talked past each other. I thought you mean the SSDs basically cannot be formatted in APFS. Because of the message: You may have to use Mac OS Journaled.

  15. MyMngy says:

    Hello Sir Apfelot,
    Unfortunately, the options listed in the start security program are not shown for me. I can only activate / deactivate or change one firmware password ...

  16. Swen says:

    I have another addition here: after buying an iPhone11 with the corresponding registration in iTunes, I was asked to upgrade my Mojave to Catalina, as otherwise it would not be possible to transfer the image from the old iPhone ...

    I then up-graded and found that my iPhone works now - but neither Adobe Creative Suite CS6 nor the LEGO software for the EV3 robot ...

    I came across your site because of the downgrade now to be considered - but the necessary rework is grueling. Does the Catalina image database or the iTunes DB hacked by Catalina still work on Mojave? The posting by Thomas Kemmer from October 16.10. speaks more of downgrade without explicit backup or with backup on image.

  17. drz says:

    Hello experts, I have the following question:

    I used the migration assistant to beam my data and programs from an old 17-inch Macbook Pro from 2011 with High Sierra as the operating system to a new 16-inch book with Catalina. That went practically completely smoothly, except for the contacts. I don't see them in the address book, not even groups. So I re-imported them from a backup (generated from the address book app on the old Macbook). I was asked if I would like to replace my current contacts - which I see as written but not. I said yes, but then I still don't see the contacts. What am I doing wrong? This problem did not exist with the calendar app, since I can see all entries on the new MB without any problems.

    Thanks in advance for your advice and Merry Christmas!

    • sir appleot says:

      Hello DRZ! Sorry for the late reply. I don't know the problem with the contacts yet. We'd have to do a bit of troubleshooting. Can you create a contact manually and then see it? Or does this not work either? If it doesn't work, I'd say one of the files macOS stores the contacts in is broken. You would have to look under Library> Application Support> AddressBook and possibly rename the whole "AddressBook" folder to "AddressBook-old". Then the Mac should actually create everything from scratch.

  18. drz says:

    Hello back, thanks for the tip, but - magic? - the contacts were suddenly there after restarting the computer. Happy New Year.

  19. PKL says:

    Hi all,

    I get the error message shortly after downloading Mojave 10.14.2:
    This version of the "macOS Installation" program is too old and cannot be opened with this version of macOS !!!

    The message can only be acknowledged with "Exit". If I try to link the "macOS Mojave with DiskMakerX to open, the following message appears:

    "Sorry, your macOS Install app may be incomplete. Delete your install application, then download it again from the App Store."

    Best Regards

  20. Carlos says:

    Catalina downgrade to Mojave with iMac 2017

    Hi Sir Apfelot,
    I come from the Windows and Linux world - I've been using Apple since Christmas ... with an iMac 2017. After the initial start-up, it immediately updated to Catalina and Thunderbird does not work properly here, so I want to go back to Mojave. Boot stick is ready, T2 does not exist, relevant data is in the iCloud. Now to my questions: Should I remove the entire system and all services from the iCloud or simply leave them so that everything is available again under Mojave?
    My 2nd question is about erasing the hard drive: according to the hard drive utility:

    Macintosh HD
    Macintosh HD data

    Image files
    macOS Base System

    Which of them do I delete, all or just one or two?
    Thank you very much in advance

    • sir appleot says:

      Hello Carlos! In principle, you don't have to remove iCloud. The Mac won't change that - even if you downgrade to Mojave. But of course, solving it doesn't hurt either.

      Because of the two volumes "Macintosh HD" and "Macintosh HD data": For Mojave, I would merge both volumes back into one (with the disk utility). However, you have to be sure that there is really no relevant data there that you don't have somewhere else. If necessary, make a backup of the Macintosh HD data, because the other volume only contains system data that you can reinstall at any time.

      Regarding "Image File" and "macOS Base System": I assume this applies to the two volumes above. If you merge these, you'll format the disk with APFS and GUID partition table anyway so that Mojave feels comfortable on it.

      I hope this answers your questions. LG! Jens

  21. Christian Schuhmacher says:

    Hello Sir Apfelot
    After upgrading to Catalina, my external (Apple) DVD player (Superdrive) no longer works: The Finder does not display it. Is there a solution?
    Many thanks for your support! - Christian.

    • sir appleot says:

      Hello Christian! I think the Superdrive has not been shown in the Finder for ages. You can actually only see it when there is a CD in it and you then open a Finder window. Then the CD should appear in the left bar. The way it used to be that it appears on the desk even without an inserted medium, is no longer the case these days. : D

  22. Ortwin says:

    Thank you very much for the great instructions. Even I managed it! ;-)))

  23. Rudi says:

    Hi Sir Apfelot, thanks for the great instructions. Thought I had the open heart surgery successfully done. My Mac turns off while it is starting up and remains dead. What could I have forgotten or did wrong?

    • sir appleot says:

      Hello Rudi! In that case I would start, hold down CMD + R and then install the system again over it. If it gets stuck while booting, there is sure to be some important file up its sleeve.

  24. sasch says:

    Thanks for the instructions, everything worked great and I am (highly) satisfied with the Mac. Now it has added value again.

    A little tip: Choose a fast and secure USB stick or something similar for the bootable removable medium.


  25. Regine says:

    Dear Sir Apfelot,
    tried to delete Catalina. The Mac crashed and can no longer start.
    there is only a black screen that says in 6 languages: "Your computer has restarted because of a problem"
    Then he tries to restart, but only manages a 20th bar, then he gives up.
    I'm afraid he's dead now.
    If there is any help, please let me know.
    Thank you very much


    • sir appleot says:

      Hello Regina! I don't know exactly how you tried to delete Catalina, but I would recommend starting the Mac with the CMD + R keys held down. Then you come into a recovery mode and can reinstall the system over it. That should help first!

  26. Regine says:

    I did it, now I'm actually back in the utility, but it doesn't recognize the mouse or keyboard. Do you have another tip?
    Thank you very much

    • sir appleot says:

      Hello Regine! (sorry for Regina) I assume you have a wireless mouse and keyboard? Then it would be a long press on the right side of the keyboard until it flashes. I'm not sure about the mouse. I think switch it off and on at the bottom and then look in the apple menu> system settings> bluetooth to see if they appear.

  27. marvin says:

    One more remark / suggestion:

    I created the stick with Install Disk Creator and somehow assumed that the program would also overwrite the file system on the stick. This is not the case! So you first have to format the stick in accordance with Apple (Mac OS Extended / GUID).

    If the stick is formatted differently, it still looks as if you could boot from it, but in step 4.6 or 4.7 ("Select your stick or your hard drive from the list" ...) it connects to the Internet and wants to - But you only notice that after an eternity - then install Catalina again. (At first I thought the Mojave installer wanted to download something from the network.)

    Jens, maybe you can chop it up somewhere up there. Otherwise: Thank you for the great instructions :-)

    • sir appleot says:

      Hello Marvin! Thank you for your hint. I'll build that into the article so that future readers don't fall into this "trap". Thank you! LG, Jens

  28. Sandler says:

    Hi Sir Apfelot. Thank you for the guide on how to downgrade from Catalina to Mojave. Unfortunately I had the option «Exclude system files and programs» activated in Time Machine under Mojave. So I still shy away from the complex downgrade.

    If I delete the iMac completely and use the Mojave installer to rebuild the old system ... Can I still access existing Mojave backups from Time Machine? I am concerned with the old iTunes folders under Mojave - can I still get them out of Time Machine after restarting with Mojave?

    Have tried in vain to find out where the new music app under Catalina saves the metadata and covers? Because if I copy the entire music folder from the iMac to my laptop, the new songs will no longer be found there by the Music app or my playlists will not be updated either (just as I put them together on the iMac). Very annoying - even after adding up over 6 hours (!!!) of phone with Apple support and a 1-hour visit to the Apple Store, I couldn't be helped, or most supporters didn't even understand my question; - )

    Thought I would ask you some questions. You seem to have a lot of Mac knowledge :-)
    Kind regards Kuno

    • sir appleot says:

      Hello Kuno! Thank you for your trust that I can do more than a 6 hour phone call with Apple Support. : D I do my best. If you have a Time Machine backup, I would choose the following procedure: Freshly install Mojave on a second hard drive and then restore the user account from Time Machine with the migration assistant. With that you should have all the data back. Also the music data. According to the Apple support website, all the data for the music app is in Catalina in the folder / Users / Music /
      I can't check it because I'm just streaming.

      • Sandler says:

        Thanks for the prompt reply. Good idea.
        So install Mojave on the 2nd hard drive (in APFS format?) And then start the iMac from this hard drive, that works? (Maybe stupid question from me, but I've never done anything like that.)
        Well, I also had an older laptop that I could use to go back from Catalina to Mojave, it would probably be easier than using a second hard drive, wouldn't it ...?

        Beautiful evening

        • sir appleot says:

          Hello Kuno! Exactly. 2. Format hard drive to APFS and then Mojave on it. Then hold down the ALT key when restarting. Then comes the selection of the volumes and you choose the 2nd hard drive. Actually, the Mac should ask you during the installation whether it should take over data from the Time Machine. If everything on the 2nd hard drive (external) runs smoothly, you format the internal one and use a program like Smart Backup to copy everything from the external to the internal hard drive. Then just set the internal drive as the startup disk under System Preferences> Startup Disk and the Mac should run "as before". : D Theoretically ... you have a nice evening too!

          • Sandler says:

            Thank you for the quick support and tips. Since I have a lot of music files and a lot of photos, I have to approach such endeavors carefully so as not to overlook any trap. As I have read, the downgrade does not seem to have been problem-free for certain users either.
            But using an external hard drive as a test, so to speak, is an interesting solution.

            Kind regards from Zurich

          • sir appleot says:

            Hello Kuno! If I had problems with the system, I would always make a backup of the entire disk first and then work on it. You never know what's going to happen. For this reason it is better to test with an external hard drive. I would do the same with a downgrade. LG, Jens

  29. Desperate still says:

    Regarding the Macbook Pro 2019: unfortunately a backup from TM from an IMac does not work on the Macbook pro: - / It would be good if someone could share a TM backup from a pure OS Mojave from his Macbook pro 2019 somewhere :-)

  30. Max says:

    Hi Sir Apple Lot,
    First of all, kudos for this wonderful tutorial. Written in great detail and easy to understand.
    A little question about the mailboxes:

    I upgraded from El Capitan to Catalina and found that the mailboxes were not taken over. (They are still available in the Library / Mail / V7 folder, but can no longer be imported).
    Now, if I downgrade from Catalina to Mojave, will I be able to import the mailboxes without any problems?

    Greetings from the quarantine in Vienna!

    • sir appleot says:

      Hi Max! You should try to see if Mail recognizes the mailboxes if they are in the "V7" folder. It is possible that the folder name "V6" was still popular with Mojave. If you copy the folder over and then rename it to "V6" and then start Apple Mail, you will quickly know whether he can use it like that. If they are displayed, everything is fine and if not, we should see whether you can first export them in .mbox format with a Catalina installation. This then also imports Apple Mail under Mojave.
      Alternatively, if you have an IMAP mailbox, you can simply create a new one and the Mac will then get the latest status from the cloud. I hope some of this helps you. LG back from quarantine in North Hesse! ;-)

  31. Lukas says:


    I just tried this with HighSierra on a Mac Mini from 2018, but I always get the error message that the hard drive (in my case the USB stick with the installation file) cannot be verified. Do you have a solution for that?

    Best regards,

  32. Christian says:

    Hello Sir Apfellot, thank you very much for the instructions. The downgrade worked well. I then set up the mail accounts and the mails reappeared. But now I have the problem that the search function does not show anything when I enter something. Do you have a solution for that?

  33. Eckhart Rohde says:

    Hello Sir Apfelot,
    I have now successfully downgraded 4 Macs to Mojave according to your instructions. Thanks for that! One more question: Should you afterwards set the Mac back to its original values ​​in the startup security utility "High security" and "Prohibit starting from external media"?

    • sir appleot says:

      Hello Eckart! That is actually a matter of taste. I usually choose low security for my Macs that I have around at home, because when you wear out the internal hard drive, you are happy to be able to start from an external backup. If the Mac is often on the go and there is a potential risk of it being lost or stolen, then maybe I would take the high security level.

  34. Wilfried says:

    Big frustration! new Macbook 16 ″ and no Mojave. practically the worse system is imposed on you as a musician. On a tip, I install Mojave through Parallels.
    It's a shame that you now have to resort to other solutions. This was not pointed out at the time of purchase!

  35. Steve says:

    Hello, how do I download OS X Mojave ??? The link leads to Apple and there is always a window with the message "Connection to the iTunes Store is being established", then a "Start application" window opens and the Music app opens. and then I get the message "Article not available". The change of country / region did not help either.

    • sir appleot says:

      Hello Steve! Yes, unfortunately Apple pulled the plug a few days ago and you can no longer charge Mojave. Sorry : /

  36. Phil says:

    Hello Sir Apfelot,
    great description. My case is a little different and I thought that would be the normal case, but after a long research I can't find anything about it.

    Did a Time Machine backup before upgrading Mojave to Catalina. After I had to find out after the upgrade that some programs in Catalina that were important to me were not allowed to start, I simply rolled back to my Mojave backup, waited a few hours and everything was fine again. Later I have to find out that the Macbook Pro (2013 Retina 13 ″) no longer has any free memory. So this "Macintosh HD data" partition from Catalina is still there and blocks 95 GB. Mojave apparently cannot use this because: after a few minutes of waiting in the system optimization for memory (which is offered by the popup) everything is added up and a total of 140 GB (256 GB internal SSD are installed) are occupied. The 95 GB of the Catalina partition (… data) are suspiciously close to the value of the missing GB.

    Do you think I can simply merge the "data" under Mojave with the Maintosh HD? Somehow I don't dare. Thank you for your assessment in advance.

    • sir appleot says:

      Hello Phil! I think I would first delete the Macintosh HD data and then merge it. Otherwise you have the problem that your data is all duplicated. But you still have your Time Machine backup in case something goes wrong, right?

      • Phil says:

        First of all, thank you very much for the super express help :) It took a while, didn't want to risk anything, it took my Macbook the last few days. Finally the time has come.

        Short report: Simply delete "Macintosh HD data" with the "Disk Utility", done. Then the Macintosh HD is back to full size, the expected + 95GB are free again. Funnily enough, the Macintosh HD data is automatically recreated by the Mojave after a few seconds. The free storage space is retained, so that’s all right now. The annoying popup (little storage space) that comes up every 5 minutes has definitely disappeared. The new Macintosh HD data is empty and is providing the storage space. I'll watch what happens for the next few months. The data backup was not required, everything was as expected.

        The backup mentioned is too old (from October). So I wanted to create a new one. That always stopped after a minute without an error message. I am sure, however, that there was simply not enough free space to create another one with Time Machine (I do the backups manually, the Time Machine automatic is deactivated). To be on the safe side it was said: old school backup of the individual files and folders in the Finder. If someone wants to do that too, don't forget these folders:
        - Documents
        - Downloads (if needed)
        - Export emails with Apple Mail as .mbox (I archive locally on the Macbook)
        - Photos: either copy the entire media library (in the "Pictures" folder) or export the individual jpgs with the Photos app (I did both for safety). Possibly not necessary for iCloud users, I also save pictures locally
        - Writing desk

        LG Phil

        • sir appleot says:

          Hello Phil! Thank you for your feedback signal. It's nice that the warning is gone and that you have "full capacity" again. : D

  37. Burkhard Koehrich says:

    Hello, you are writing new iMacs that already have Catalina on it and cannot be downgraded. Since I bought a new iMac with Catalina on it (7 days ago) I wanted to install a virtual El Capitan on Parallels, because I still have a lot of 32-bit programs from the older Mac and then run them over El Capitan (also have the last backup via Time Machine, but Parallels would probably also run this via migration). However, the problem is that an error message also appears when installing after booting Parallels. Is there a solution for new Macs via Parallels to get an earlier MacOS on it as a virtual environment? vg, Burkhard

    • sir appleot says:

      Hello Burkhard! Unfortunately, I can't try that because I don't have a new Mac. But if you write that there are error messages, it sounds like it doesn't work. What exactly do the reports mean? And when do they appear?

      • Burkhard Koehrich says:

        During the installation, after the installation is 50% advanced and has already rebooted, the error message appears that the installation cannot be continued because the package cannot be accessed. A restart or reinstallation leads to a login loop that remains unsuccessful.
        According to Parallels, it should actually be possible. Didn't find anything on the net that indicates this problem. What I can possibly still try is to install a virtual environment on the old Mac and copy the virtual environment, which is a package under Parallels, onto the new Mac. Whether this can then be carried out is then still questionable, but it also worked in the old Windows environment.

        • sir appleot says:

          Hello Burkhard! Thanks for the description. I don't think I can contribute anything helpful. But maybe other readers still have tips.

  38. DM says:

    At first I was able to downgrade a Mac mini that came with Catalina to Mojave. The security settings and the logout to "Where is?" I had already done it, but the thing still refused. I then connected the Mac mini via Target mode (hold down the "T" key when starting) to another computer with Mojave and cloned it from there via Carbon Copy Cloner. That worked!

  39. theSven says:

    I received a MacBook Air 2020 with Catalina. Now I would like to downgrade to Mojave. I made the start security settings and then deleted the disk.
    When starting from the USB stick, everything works up to the point where it reports that: Bless-Tool cannot select the start volume.
    What could be the problem? How do I get further?

    • Jen Kleinholz says:

      Hello Sven! Unfortunately, I've never heard of the Bless Tool. I think there was a problem with playing a Mac on a system older than the one it came with. Maybe you can start the installer and first install the system on an external hard drive. I think that was the trick.

  40. Bert says:

    I followed the instructions and got to booting the MOJAVE install file.
    The loading bar ultimately shows 100% and then nothing more happens.
    Do you have any idea what the problem may be?

    I have an older MacbookPro.

    Greetings Bert

    • Jen Kleinholz says:

      Hello Bert! Unfortunately, I have no idea what the problem could be, but give it a try with a bootable USB stick that you have with you anyMacOS can create. I think the software will download all installers from High Sierra for you. Mojave should be there too.

      • Bert says:

        Hey Jens,

        with a little patience I have now installed Mojave.

        Now I want to downgrade to Sierra.

        I am following your description to delete the OS.
        You describe in point 8 that "If you want to prepare your hard drive for deleting or formatting for an older operating system (up to 10.12 Sierra), then choose the HFS + file system".

        Only AFPS options are suggested to me?

        Can I only install Sierra with HFS +?

        Is it possible to install Sierra with AFPS formatting?

        • Jen Kleinholz says:

          I think you have to first select "GUID Partition Table" under "Scheme" and then use "Mac OS Extended (upper / lower case, journaled)" under "Format". The name HFS + is no longer used in Disk Utility. This is a bit confusing and I would have to correct it in the article. That should be right for Sierra. APFS is only available from High Sierra - so a version according to your "macOS wish". ;-)

      • Bert says:

        Hey Jens,

        with the help of Apple support, I was also able to overcome this hurdle.

        Instead of the key combination alt + R, the key combination Shift + alt + cmd + R is required to get into the corresponding recovery mode. There you then have the option of selecting "macOS extended journaled" (corresponds to HFS +).

        Thanks for the guidance.

        Greetings Bert

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