An error occurred preparing the software update - Big Sur

seems the internal installer is getting stuck at this point. Not sure what caused it but I did purged NVRAM multiple times so that might be the reason.

after doing what you suggested, instead of bringing me to the desktop of the mac, it loads back up the update and the cycle continues

Yes! I found the same article! Mr. Macintosh lifesaver! Everyone was saying I'd have to wipe too, glad you managed to get yours sorted as well.

I can’t update my Mac book ... it showing error every i tryna update I can’t even use my laptop

Try Disk Drill, the basic version will allow you to see all the files (scanning takes a while, be patient).

I am able to extract the files and currently transferring 400+ GBs of data. (for me, all the (valuable) data files are in the /User, so I don't care about applications, system files etc). Just need to get that directory copy over.

I've noticed several files I've extracted are corrupted, but I guess that's the cost of screwing up update.

And for some reason Disk Drill will actually take your pwd, while Apple couldn't.....

Any way, feel really sorry for the folks who wiped the disk. Data still there, and the Macintosh HD still verify the correct pwd.

Many thanks to the guy who found Disk Drill.

Ok so I was able to follow what guysboi said. At first I could not locate the Macintosh HD - Data volume on Finder.

But I saw it on Disk Utility and right-click and chose Show on Finder, and I finally found all my files and was able to copy them to my external hard disk and delete big files to free up space.

I am now redownloading Big Sur on my Macintosh HD, now with enough space.

To find your files from Macintosh HD while booted on an external drive,

>go to Disk Utility and

>right-click on Macintosh HD - Data and

>click Show on Finder.

All your files from Macintosh HD will be there. I did and I was able to save my files, and free up space on my Macintosh HD. So happy I didn't have to lose any file at all.

Thank you for your help guysboi!

Just found a solution for those, who cant open their HD on another mac, because the FileVault password is unrecognized.

First, find another Mac who has an older OS. I used Mojave.

Now, on your "broken" mac you will have to enter the target disk mode (which is offered after the error message)

Then connect your "broken" mac to the other Mac with an older OS.

Enter the FileVault password. NOTE! This will not work if you connect your laptot to a Mac with Big Sur. Then the password will be unrecognized.

And there you go, copy all your files to a hard drive.

Next time, back up, before updating to a new OS ;) I definitely learnt my lesson...

I also had this problem, disk drill could recover some of my files, but some were corrupted. When I tried target disk mode connected to a computer running Mojave the password was recognized and I was able to delete enough space on the problem computer to let Big Sur finish installing, and the files that disk drill showed as corrupted were fine!

FIXED!!!!

after 9 hours of messing with this and 1 hr. On the phone with apple support. here’s what finally worked:

First some Details:

Machine - MBP 2018

SYMPTOM:

Update locked out halfway through install after the restart, displayed message “An error occurred preparing the software update”

FIX:

after trying every other less drastic system recovery method, I finally reformatted the hard drive by performing a hard shut down from the locked up install screen, entering disk utility recovery mode (by holding: command, option, R - during boot up). Then following the steps until coming to the screen that allows you to enter the disk utility recovery. From there Enter disk utility, erase hard drive first and then erase data drive. After that installing Big Sur from system recovery screen worked, though I later opted to restore from a backup of a previous OS using this same method.

if even the Big Sur install was so buggy, I don’t feel it bodes well for the rest of the OS, and don’t care to waste anymore time with more bugs like this. So downgrade was the clear solution to me. Maybe everything else works fine with it, but at this point I’m not taking any risks with such a time consuming bug this early I the game ;)

Hope this helps.

Apple personnel aren't here. We're all users like yourself. If you want to talk to Apple call the number at the bottom of this page and ask for Customer Support.

Make sure you don't have a file in the Applications folder titled "Install macOS Big Sur.app". If you do then delete it, wait a day and try again.

Also, sometimes the servers are very busy or have outages. This can cause the updates to not download & install. The same thing happened on November 12, 2020, when Apple had released BigSur.

You can check the Apple System Status at: https://www.apple.com/support/systemstatus/

Hi

I had the exact same errors. MacBook Air late 2018. 128gb

Im not clued up on all the workings of a Mac for when things go wrong but had to teach myself

In the end I did the following it meant I lost everything on the MacBook but I was lucky and everything was stored elsewhere. I still don't have Big Sur installed but Ive got a working MacBook. I followed the section for selling on your Mac

1) erased and removed the MacBook via the "find my" app

2) Forced shutdown by pressing the on/off button

3) Command R which installed the original OS - Mojave in my case

I did have issues where it didn't recognise the disk to install it on but I clicked on the partition button and followed that

I then updated to Catalina via the App Store.

https://apps.apple.com/gb/app/macos-catalina/id1466841314?mt=12

Hope this helps

I have the EXACT same problem as you have listed. I have a MBP 2019 13' 2port.

I even tried reviving BridgeOS via using apple configurator 2. That didn't work out as well.

I would suggest we move this discussion on to the developer forums for more technical talk, this problem has been causing massive inconveniences for me and Apple needs to know about this.

I have the exact same problem. My local apple service workers say that the only solution will be to completely reinstall Mac OS with all the data on your laptop being lost if you dont't have a backup.