an error occurred applying the software update

We had a similar problem with my wife's iMac (21.5" 4K). Some error, undefined, was reported and the computer kept booting to the slash circle.

So yes, first thing, do the Cmd-R boot, then open Disk Utilities and run Disk First Aid to clear up any potential problems.

Quit then go to the install screen and Big Sur should be a choice. Also make certain your drive is showing.

What I think happens sometimes is that the installer gets interrupted or corrupted and then the computer is left in an unstable state.

Same error happened to me 💔

Also, I'm a graduated student and really need Apple support to help us ASAP please 💔

I don't want to erase everything because I have my projects and reports for the college and no copy for them 💔

Please help us.

Hey I had the same problem but I have a solution. What you do is you restart your mac on the screen where is says an error occurred while applying the update and as your computer starts hold down command and "r". Then it will start macos recovery. There you choose your user and type in the password and then choole install mac os big sur. It will download a fresh copy of the update and install it. It worked for me hope it helps.

Same thing happened to me. After being on the phone for 2 hours with support the only option left was to erase everything and reinstall Mac. It loaded Mohave back, I tried Big Sur again and the same thing happened. 🤦🏻‍♂️

It seems that things are worse for me. I can start in Mac OS recovery and I can see my user account but password doesn’t work. If I try to access by using Apple ID same thing: my password doesn’t work. If I boot in safe mode and try to access the network, once again the password doesn’t work. I’m sure passwords are right. Any idea?

If you can boot to the recovery mode then you have access to Disk Utility.

Not accepting yur password for the User probably means either it is trying to access a different drive/user or the User got corrupted (an old problem not seen much anymore).

When Recovery mode comes up, if I remember correctly, you see a screen with a language choice then you proceed to the next screen which could be an installer or choice screen.

At the top of the window you will have a menu bar, in the rightmost menu you have access to some tools, like Disk Utility, Terminal and such.

Run Disk Utility, see what drives list on the left side. Choose your start up drive and then run Disk First Aid on it.

Also, if things fail to resolve but you are in the Recovery mode then you will have access to use the Time Machine backup drive.

I d hope it is a separate drive.

Again, when I resolved my wife's iMac problem I was able to boot holding the Option key down and saw the drives list on the scfreen.

Sorry to hear. Not fun. I wish I had more answers to help. My only suggestion is to try and contact Apple and see if they can help. Good luck to you. I know this is beyond frustrating. PS - I know I am on borrowed time as I can hear my hard drive starting to make noise. UGH! So frustrating. I am going to go get a WD - My Passport Ultra for Mac 2TB External USB 3.0 Portable Hard Drive and use Time Machine ASAP. Be well.

https://support.apple.com/en-us/HT201232

Same issue. No colume to recover in MacOS Recovery as well. Donno how to do now

My Macbook air (2018) model was running properly with latest MacOS Catalina.

I tried MacOS recovery but cannot reachthe disk utility screen. No users on this volume to recover......

Have you tried simply booting holding the Option key down?

If there are drives that can be seen this should show them. PLUS, you might also have a Choose Network below the drives listed. If you see that then select the appropriate network and log in before proceeding.

I had to do that with my wife's iMac and it showed surprisingly 2 drives named Macintosh HD and the backup external drive. If so, I selected the 2nd drive because the undefined state your computer has been left in may be trying to boot to the Data part.

Also, don't you have an external Time machine backup?

If it shows only one drive then try proceeding to boot to that.

Chatted with Apple Support and tried all the methods mentioned. Still couldn’t resolve the issue.

Then called with their phone support and spent 1 hour with them. Still couldn’t resolve the issue.

Apple Support booked the service center. I went there in person today and spent 2 hours there.

Finally they helped to reset and re-install the MacOS Big Sur to my Macbook Air.....

Thanks a lot for your Help! I downloaded a Catalina installer and tried to use it to recover the system, but it doesn’t work and it seems that it is due to the fact that the disk is encrypted (I saw it using disk utility). I don’t remember I had never decided to encrypt the volume and I don’t have a password to unlock it..

Don't upgrade to Big Sur OS 11 till they fix it

the upgrade has affected our business and productivity.

it has affected all devices - can’t print, can’t used some apps that were from AppStore and other sources.

It has affected seamlessly transferring data between apps and devices.

There is disastrously reduced number of OS11 apps in AppStore. Even some of those were not working effortlessly like the earlier version.

You were using File Vault to encrypt your User Folder.

Need to call Apple for help as that is a whole different issue.

They clearly state if you are using File Vault then you need to turn it off before doing an update. But if you didn't knwo, hmm.

Good luck.

Two many people have auto updating turned on, and that isn't the best way to go.

And many problems weren't the result of the installer, but of some unexpected interruption like the internet droping, or stopping and restarting the download/update, or the drive too full or file Vault turned on and not turned off or some disk repair wrok needing done first.

Every app I use had an update. The only ones that wouldn't update before the OS upgrade were those requiring Big Sur to operate. Many other apps work better in Big Sur than they were in Catalina.

As for businesses, usually the IT person does the proper checks before any major updates are done.