An error occurred preparing the software update - Big Sur

Hi Tracy,

I see, that sounds like a reasonable way to go. I agree it shouldn't be that hard to upgrade an OS. I've been a Mac user just as long, since the early 1990s.

You could even do this, clean install Mojave > restore your data from Time Machine > upgrade to Catalina and then apply the Big Sur upgrade once you install Catalina. It shouldn't matter though but somehow it's not liking Mojave for whatever reason.

Hope this helps and do keep me posted.

Hey Soren, I want to close the loop on our journey . . . I broke down and took my MBP to an Apple Store today. They were able to successfully do the install of Big Sur from their on-site server. However, the also noticed a kernel problem during start up - a single screen that said essentially that the "computer has encountered a problem during start up. wait a few seconds or hit any key to resume". But everything else seemed to be functioning. This led them to do a full diagnostic on the MBP where they determined that the hardwired memory was degrading. They believe this "likely" was the cause of the erratic behavior that we were seeing during the macOS downloads, the the OS installs, the recovery modes and even safe mode. It's possibly why we could not get reproducible results.

So bottom line is that you and I were following all the normal steps but the hardware likely was the problem. Probably a rare event since most memory failures occur slowly over time, not during single events like OS installs. . . . . so I'll go to my local go-to Mac guy for the repair, which should get me back into the normal Apple universe. So in a sick, twisted way, the past 5 days of macOS installation **** has been good because it means we caught an annoying problem now before it became a major problem later (which always occurs at a critical time according to Murphy's Laws).  . . . . thx againd for your help and suggestions . . . rgds . . Tracy

Hi Tracy,

I appreciate you updating me.

That's good news that Apple was able to get Big Sur installed from their own server. I believe the installer does a hardware check which could be why the install failed. Failures don't usually become apparent until one upgrades MacOS or the firmware is updated during install.

Interesting about the memory degrading, one thing you can run and would have recommend was Apple diagnostics. It can be run by holding down the D key when you boot your Mac. The diagnostics at the store could be more thorough but apple diagnostics does check the hardware and gives you an idea of something is amiss.

Good luck getting your RAM taken care of by your local Mac guy. Rossmann Repair Group is another place if you need it.

Hope the apple store appointment wasn't costly.

My pleasure and it was great helping you out.

Hi dddeeennn,

Yes, boot back into your Mac normally if you able to and then perform a time machine back up.

Also, refer to my post that I just shared for additional information.

Hope this helps.

Hi mohammadskhv,

Refer to my comment earlier to solve this issue.

Hope this helps.

I tried doing the same. But my MacBook Pro got stuck in a blank screen that just displays the symbol as shown in the pic.

I see this blanked out symbol after trying to select Mac HD. Please help!

I am trying to login through the macOS Recovery mode, but the system DOES NOT ACCEPT my VALID credentials. I am pretty sure the password I am typing in is CORRECT.

I also tried password recovery and gave in my Apple account credentials.

But here is what I see-

Happening to me now, trying to follow suggestion from AshleeyDee91, shutdown-press option-max hd, the process only repeating the same, need advise please. Need my macbook for school tomorrow

Hello, when I do the following steps the this appear. What do I do after this. Please help

After I press command R it says to put my password but when I put it says it’s incorrect.

I have tried to do this as well but only get the macOS Installer option. Please can anyone help??

Thank you for the info. I sadly have only the macOS Installer I can’t access any other drives. Is there any other way?

I tried it, and it was loading so i thought it worked, but then this screen popped up all of a sudden: