macOS Big Sur Error: Installation Failed

macOS Big Sur Error: Installation Failed

Like every year, yesterday I jumped at the new macOS update with joy so that I could try it out on my MacBook Pro as quickly as possible. Unfortunately, the download of macOS Big Sur dragged on like chewing gum and at some point broke off completely.

A repeated initiation of the update showed a rapidly growing progress bar, but then it stopped again. After a few minutes of delay, the following error message appeared:

Installation failed. There was an error installing the selected updates. [OK]

Thanks for this informative error description ...

I love it when error messages really make it easier to research the cause ...: D
I love it when error messages really make it easier to research the cause ...: D

macOS update error keeps coming ...

So far the mistake wouldn't have been tragic, but unfortunately it persisted. As soon as I started the update again, the Mac stopped with the above-mentioned "Installation failed" message.

I thought a reboot should fix the problem, but in this case even this miracle cure failed IT Crowd. Even after a complete cleaning run with my favorite make-up program clean my mac x the error message was there again.

Key combination CMD + ALT + R when booting? Didn't help either ...

Another idea was to cheat the Mac with the key combination CMD + ALT + R at system start, because this will install the latest macOS on the Mac that is still running on the device. In my case, that would theoretically have been macOS Big Sur, but unfortunately the recovery only suggested Catalina to me. I suspect because Big Sur is not yet known as a recovery system on my Mac. Anyway, the path was also a dead end.

If you reinstall macOS over an existing installation, no data will be lost, but the system files will be repaired or replaced. This solves one or the other error - as well as this update error.
If you reinstall macOS over an existing installation, no data will be lost, but the system files will be repaired or replaced. This solves one or the other error - as well as this update error.

Solution: Time and money installing macOS Catalina

Ultimately, the following procedure brought improvement: I called the recovery mode with the key combination CMD + R when booting. In its menu you will find the item "Reinstall macOS", which I have chosen.

This installed macOS Catalina again over my existing Catalina, which took almost 1,5 hours. I went to sleep in between.

When I brought the Mac out of hibernation the next morning, Catalina's login screen was visible and a click on the refresh button started the download of macOS Big Sur again. This time with success, because the bar ran through completely and the Big Sur installer appeared.

Back up macOS Big Sur Installer

At this point I quickly dragged the “macOS Big Sur Installer” in the Applications folder onto my external hard drive so that I had it ready for future actions. But you can also get started right away and install the system.

After all this action, I am running macOS Big Sur - and it is very stable. I can't complain!

Perhaps the instructions will help one or the other who also sees this error message. Often it doesn't seem to happen, but if it hits someone, they may be happy about this post.

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20 Responses to “macOS Big Sur Error: Installation Failed”

  1. I have a completely different problem when trying to install Big Sur. At the point where I specify where Big Sur should be installed, the installation process tells me that the disk does not have enough space. Also says that he needs about 6-7 GB.

    But the disk has 50 GB free. I have no idea what I can do here.

    Does anyone have any idea?

    1. Hello! Unfortunately, I did not come across that and I have no idea how it comes about. My suggested solution would be: Install Big Sur on an empty external hard drive. Then move everything from the internal one with the migration assistant. Then delete the internal and copy everything back from the external to the internal. It's best to make a backup of the internal one beforehand, which saves the Catalina state. : D

  2. My Macbook Pro Retina early 2015 with 8GB of RAM totally collapsed with Big-Sur. Got Catalina back on it. Today on November 16.11.2020, XNUMX a Catalina security update came - since then Bluetooth has been over, despite deleting the BT plist in the library and deleting PRAM.

    1. Hello Mio! That doesn't sound good. For me, Big Sur even feels faster than Catalina - and that on a 2017 MBP. Maybe you will give the system another chance? LG, Jens

  3. Also having problems installing Big Sur.
    The first attempt broke off and I couldn't get into my Mac at all. Tried keyboard shortcut cmd + r to restart Big Sur from recovery. Installation canceled again. "An error occurred while applying the software update" is the message every time.
    In the hard disk utility run first aid through every hard disk, deleted, tried again, canceled again. Apple Service doesn't help either. Wine now at a loss, don't know what else to try.

    1. Hello Leon! What kind of mac do you have Is it more of a new model? Or an older one? Perhaps I would try again to connect a freshly formatted external hard drive and install Big Sur on it via Internet recovery (cmd + Option + R when booting). Your installation file may be damaged. He should actually reload it for Internet recovery. Will you let me know if that helped? LG, Jens

      1. Hello, Jens!
        I have a MacBook Air (2017), so as far as I know, it is an option for installing BigSur. It would be strange if not, at least I was informed that the update is available.
        I think I'll try that with the hard drive. Any tips on what to consider when buying the external hard drive? I'm more of a layman in this field.
        With kind regards,

        1. Hello Leon! If you install the system on the hard drive, I would always recommend an SSD. Here would come for example SanDisk ExtremePortable in question, which is currently heavily reduced in price. I have already recommended it to a few readers and everyone was satisfied - like me. If a little more money can be used, you could too Samsung T7 to take. It has an even higher speed, which of course has an effect when working. Both SSDs have USB-C and are therefore suitable for your MacBook Air.

          1. First of all, thank you for the recommendations!
            You said about the Samsung it was faster, which for example affects the work. Does that mean that if I perform the installation using the external hard drive, I always have to connect it to the MacBook in order to use it? Isn't there the possibility to somehow run the system via the normal internal? Or do I have to wait until I install the next update via the internal one, for example?

          2. Hello Leon! I understood it to mean that you first want to install the system on an external hard drive to be on the safe side. If you do that, it must of course be connected in order to use the system. If you then notice after 2-3 weeks that everything is going well, you can also install it on the internal hard drive and then no longer need the external hard drive. If it is just a temporary solution, then I would take the Samsung. It's cheaper and very fast.

  4. Hi Jens,
    I have a problem where even the appletechnicians are overwhelmed.
    When installing via a boot stick, the process is aborted if there is a remaining time of 15 minutes.
    The error message is:
    The operation could not be completed. Permissively denied.

    Meanwhile I don't know what to do next.

    The second problem now is that I've already deleted the HD. He always breaks off a recovery from the timecap.
    What can I do.

    PS: I saved the date on an SSD.

    1. Hello Dennis! It can always be that the boot stick is defective or that it is stuck somewhere. In that case I would try a different installation method. It is important that the hard disk on which the system is to be newly formatted and does not contain any data from the old system. That seems to have been taken care of by you. Now restart the Mac and hold down the CMD + ALT + R keys. The Mac boots into Internet Recovery mode and gets the system fresh from the Internet. The latest version of macOS that your Mac supports will then be installed.
      When that's done I would let the install run and not pull any data over, just skip the import and start with a fresh user. Only then can you attempt to restore the data from Time Machin using the Migration Assistant utility. Maybe this way. LG and good luck!

  5. When upgrading to Big Sur, when selecting the volume on which to install Big Sur, the message "The volume cannot be used because it is a backup volume" appears, even though it is the Macintosh HD volume. And the Time Capsule is used as a backup volume.

        1. Ok, weird. My workaround would be to format the volume again and then try again. If that doesn't work, I would install Big Sur on an external hard drive and then clone it to the internal one using Carbon Copy Cloner or something like that. There are some mistakes that you just can't get rid of. :-(

          1. Tried a little. Apparently the problem was that access to the hard disk was blocked (lock symbol closed). After I unlocked it, the upgrade worked.

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