An error occurred preparing the software update - Big Sur

Hi mohammadskhv,

You should have read my comment about this to save you the hassle.

You didn't need to erase your Mac and you wouldn't have had to loose anything.

You could have used another Mac to create a bootable USB stick of Big Sur or even Catalina and used that to reinstall just the operating system and you would have been up and running in no time.

I'm glad you had a backup.

If you wish, I would consider upgrading to Catalina if you want to hold off on Big Sur as Catalina has been out longer.

Hope this helps.

Hi Brandontjo,

If you didn't erase your drive you should be fine and your files are safe.

The prohibitory symbol means that your Mac contains an operating system but it's not able to boot to it.

If you have another Mac and a 16GB USB drive you should be able to reinstall MacOS onto the said Mac from the flash drive and be good to go. How to create a bootable USB drive of MacOS.

Once the USB drive is created, put it into the USB port of the Mac having issues. If it's on turn it off by holding down the power button.

Next, press the power button to turn it on normally and then hold down the option key and let go when you see a screen showing a few volumes. In the boot selector, you would choose the drive Install MacOS Big Sur with the arrow keys and hit enter to boot from it.

When it's booted off the USB, click reinstall MacOS Big Sur and follow the prompts to continue.

The data is restored from a time machine back up.

Hope this helps.

Yes guys..... do not update to big sur PLS!!!

i had the same issue: macbook asking for your password to your account but the password not working, my macintosh HD password didn’t even work and eventually it would not even show up anymore.

I was on the phone with Apple Support for 4 hours and they could not help me.

we tried everything: Command R, Shift option command R to get to the macOS Recovery, but i had no backup with TimeMachine, disk utility didn’t help...

even tried to use an USB stick to download El Capitan on it and sort of transfer it or something and tried to use ‘resetpassword’ in Terminal but no...

my internal harddrive was not found even though with Command R you could see that my account was still there.

When in El Capitan on the USB, it was showing as if the internal harddrive was completely empty.

i ended up just having to use command shift option R to use ‘reinstall OS X’ which led me to OS X El Capitan again (now without the USB)... with zero of my old files. I started blank and without all my photos/files for uni, everything.

just don’t update to big sur pls.

(i also believe this error occurred bc of the low storage i had but i’ve heard a lot of issues with the update in general)

Catalina or Mojave is fine really, so pls don’t take this risk like we did bc i for sure lost everything.

the most stressful day ever.

Hi,

It should have caught it, but in my case, it didn’t. And I could perfectly install the Big Sur to the external HDD and later to my deleted, totally empty Mac. I was only able to go back into my operating system when the phase I have mentioned first happened: when the software had been installed to the external HDD. Before that, I couldn’t. I could not log into the computer. Of course not only a lack of space but a damage on the disk could occur. Although it seemed to me that the lack of space was the problem, since I only had like 9G free space on my Mac and it wasn’t caught early enough by the installer. Anyways, with the help of the two external HDDs, I could solve it.

Thank you for asking.

Hi Tracy,

Thanks for getting back to me.

That's strange it won't boot into safe mode when holding down the Shift key at boot. You mentioned the symbol for not allowed, you mean the circle with the line through it? It looks like this:

I have four things things you can try:

1. Reset the SMC
2. Reset NVRAM or PRAM
3. Search for Disk Utility in Mojave and open it. Next, click First Aid in the menu bar to see if it finds anything wrong with your drive.
4. Reinstall MacOS. Boot into recovery mode by holding down command r at boot and double click reinstall MacOS from the MacOS utilities window. This will reinstall just the operating system which should be Mojave and not touch your files. Having a backup is a good thing and based on what you've said you have one which is good.

After reinstalling MacOS Mojave you can try the installation for Big Sur and hope it works.

Hope this helps and keep me posted.

akl_17,

Thanks for replying, I will be happy to help.

You need to back up your Mac before doing anything as erasing will cause you to loose data as it will erase the disk even if it's the disk update. Always back up before erasing or doing anything. Unmounting will not cause data loss but always best to be safe then sorry.

Hope this helps.

While I was on apple support, they told me to shutdown the computer.

Then they told me to press cmd+control+r while I turn it on again. After 5 or so minutes I was at a screen that told me to login but the computer wouldn't let me login and was telling me that I entered an incorrect password.

So apple support basically told me that I had to

1) try to connect your macbook to another computer and try to keep some of your data

2) erase all the data and go from there.

So I'll be going to the apple store tomorrow and see what happens but It is not looking good for me.

Couldn't boot via safe mode. Finally, I resorted to recovery, but I had to erase contents of my disk first, and then continue the installation of Big Sur. Apparently the low storage space I had left really caused the problem. Now I'm in the process of reinstalling apps and catching up with my relevant files (no Time Machine backup, so...)

Thanks.

Interesting. Having a backup of your data plus a usb stick of macOS so one could boot off it I feel is a good idea.

I feel if one has a backup they can erase the drive if they are unable to reinstall macOS and then restore from back up and then reinstall Big Sur once they have enough disk space.

Hi LizethBo,

Thanks for the photo. I assume you are entering your correct user password.

Do you know if you have a firmware password enabled?

What happens if you click forgot all passwords?

Hope this helps.

Well I finally got mines fix, but I had to erase everything on my computer. I contacted Apple and that was the only way to make my computer work again. It was like I just bought it Everything was lost, but when I downloaded all the apps again everything that I did was there.

That’s what I was going to recommend next, wipe the drive.

it’s always good to have a backup if something like this happens so you could restore your data. Hope you didn’t loose a whole lot though. I remember loosing everything once so know how it feels.

what version of macOS are you running? Do you plan to upgrade to Big Sur, I’d recommend upgrading to Catalina if you can as that’s a good and stable operating system.

Hi Brandontjo,

Thanks for your reply and glad what I said was helpful.

How did you reinstall the stock OS, recovery mode by holding down command r

If you partitioned your drive and ended up deleting a partition in the process all data is lost. With Catalina or Big Sur Apple changed the way the drive is structured. For example there will be a drive that says Macintosh HD - Data and Macintosh HD for the operating system.

If I were you, I would try to upgrade to MacOS Catalina, it's been around longer and more stable or Big Sur if you feel like it.

Hope this helps.

I assume you made the usb drive correctly using the createmedia command in terminal?

All USB drives are formatted as fat32 for Windows but they don’t come with a windows OS. When you enter the createmedia commend in terminal, it will ask if you want to format the usb drive which will erase everything on it in order to install Big Sur and format it for Mac. You’ll type y for yes and it will say formatting 1% 20% 40% etc.

It can take a while for it to boot off of though.

Hope that helps.

Hi,

I brought mine to a 3rd party to help reinstall the OS and they looked at it and said along with the space issue, my firmware was out of date and that is why I had a mess with my machine. Losing my data, but that’s ok.

450 aed for the update and reinstall.

Wish you all much luck

thanks,