Big Sur fried my computer Again!

[PatiPhillips]

I posted this on another forum but no replies so thought I would try here:

Automatic Big Sur update, now will computer not boot. Long story will just try to make it shorter:

Late 2015 imac had been updated to Big Sur Beta from Catalina: then last year Big Sur beta update (2.something I think) caused looping. (possibly due to Norton).

Tried everything found on internet. Finally had to erase all and migrated from my 2019 apple laptop air which is running Big Sur.

When trying everything to fix the problem last year I must have used something from my older 2013 imac because now my 2015 imac thinks it is not compatible with Big Sur and Disk Utility says I have to reinstall El Captain. (I ran repair on everything listed) my Mackintosh HD was not there just data disk and (my passport disk which I had originally used with the 2013 imac. I would install El Captain and update until at least Catalina to get my computer back... BUT ... using Disk Utility it only finds the mypassport backup disk which it says it cannot install to.

There have been a couple of updates to Big Sur that went smoothly until this one.

I am at a total loss. I am getting older and cannot remember how I migrated my OS last time. My computer is now a circus and I am feeling like a clown for allowing an automatic update which I thought I had disabled. I am beginning to dislike Apple as much as Windows!

I live 125 or so miles from the nearest apple repair and with Covid I am not even sure they are open. I am Apple poor and do not want to purchase a new one.

Anyone else have a problem with this update or have any idea how to fix this?

 

[tincan11]

Hi, if you are booting to El Capitan it is likely that something went wrong with the hard drive one way or another.

El Capitan cannot see APFS formatting, but it should at least be able to find the drive is there to erase it.

Try booting with Command, Option, and R. If you still get to El Cap and not Big Sur something is wrong.

Hold D at boot to run diagnostics to see if it says there is something wrong with the hard drive.

Try calling Apple maybe.

 

[Apple_Robert]

I would backup your important data and then install as new, instead of migrating data. If you still have problems, it may be a little easier to narrow down the whether it is an OS bug, a third party of corrupt data from migration.

 

[PatiPhillips]

Hi, if you are booting to El Capitan it is likely that something went wrong with the hard drive one way or another.

El Capitan cannot see APFS formatting, but it should at least be able to find the drive is there to erase it.

Try booting with Command, Option, and R. If you still get to El Cap and not Big Sur something is wrong.

Hold D at boot to run diagnostics to see if it says there is something wrong with the hard drive.

Try calling Apple maybe.

I tried command option and r. This time it did give the option to install Big Sur but no mouse working no keyboard working. Tried D at boot, still no mouse working but hitting enter started the diagnostics. Said no issues found. Back to square 1. I may try to call Apple. Thank you for the suggestions.

 

[Honza1]

I am still not completely sure what you had and happened - it is bit confusing. But you have iMac 2015 which was on BS and automatic upgrade caused it to loose system and now it boots in recovery(? - that would be possibly ElCap). Any upgrade stresses drives more than regular operations and that is why you see all these reports on "XY MacOS upgrade fried my computer" here. If drive is close to failing and upgrade is run, it fails. Failure is not caused by upgrade, but is hastened by the upgrade. Happened to me also, this is not unusual.
You seem to have another Mac. So here is what I would do - you will need to google instructions or search this forum, this has been described in number of places.
1. Reset PRAM and NVARM (cmd-opt-P-R on boot), may be those are confused
2. Get USB (USB3 preferably) flash drive, I think you need 16GB size and find how to make bootable installer of Big Sur. It will be easy if your Air is running Big Sur, but you need to download installer from Apple store. I saw recently post that someone made one-button GUI for that. I think it was here: https://forums.macrumors.com/thread...-m1-mac-mini-from-recovery-partition.2280836/
3. Unplug the hard drive with your data and boot on this USB flash drive.
4a. If the main iMac drive is visible, format the drive as APFS and install BS.
4b. If the main iMac drive is not visible, buy new SSD drive for your system, install and follow 4a.
5. Use migration assistant to move your data back.
If this does not work, call Apple support and see what they can do.

 

[PatiPhillips]

I would backup your important data and then install as new, instead of migrating data. If you still have problems, it may be a little easier to narrow down the whether it is an OS bug, a third party of corrupt data from migration.

Can't start computer to back up but I do have time machine backups. I don't think I can install as new if I can't boot up? Thanks though for the suggestions.

 

[Jack Neill]

What OS were your backups on? If you can get to Internet Recovery, let it wipe everything and then restore your backups?

 

[PatiPhillips]

I am still not completely sure what you had and happened - it is bit confusing. But you have iMac 2015 which was on BS and automatic upgrade caused it to loose system and now it boots in recovery(? - that would be possibly ElCap). Any upgrade stresses drives more than regular operations and that is why you see all these reports on "XY MacOS upgrade fried my computer" here. If drive is close to failing and upgrade is run, it fails. Failure is not caused by upgrade, but is hastened by the upgrade. Happened to me also, this is not unusual.
You seem to have another Mac. So here is what I would do - you will need to google instructions or search this forum, this has been described in number of places.
1. Reset PRAM and NVARM (cmd-opt-P-R on boot), may be those are confused
2. Get USB (USB3 preferably) flash drive, I think you need 16GB size and find how to make bootable installer of Big Sur. It will be easy if your Air is running Big Sur, but you need to download installer from Apple store. I saw recently post that someone made one-button GUI for that. I think it was here: https://forums.macrumors.com/thread...-m1-mac-mini-from-recovery-partition.2280836/
3. Unplug the hard drive with your data and boot on this USB flash drive.
4a. If the main iMac drive is visible, format the drive as APFS and install BS.
4b. If the main iMac drive is not visible, buy new SSD drive for your system, install and follow 4a.
5. Use migration assistant to move your data back.
If this does not work, call Apple support and see what they can do.

Thank you Honza1, I will try to attempt some of this and see where I get.

What OS were your backups on? If you can get to Internet Recovery, let it wipe everything and then restore your backups?

My backups were on catalina/big sur. I did erase the disk and loaded big sur (downloaded the installer with my laptop, moved it to a usb drive and put on my desktop. I now have big sur and no data. Can't restore backup because now I have a kernel panic that interrupts getting everything. Trying to figure out how to fix that now! So far have tried to reset SMC, that did not work. Computer restarts every 15 min. Frustrated to say the least.

 

[Honza1]

If you now have clean fresh Big Sur instal and your system has Kernel panic every 15 minutes, it is looking like hardware failure. Macs do not have kernel panic with clean system (especially .2 version) unless there is something wrong. iMac is telling you something this way.
You could try wipe and install older system (they can be downloaded from Apple) - it is possible prior system may be more forgiving to whatever is going on with this iMac. But something is out of spec. If there are logs to this kernel panic, someone smarter than me might be able to tell you which part of system is causing it.

 

[PatiPhillips]

If you now have clean fresh Big Sur instal and your system has Kernel panic every 15 minutes, it is looking like hardware failure. Macs do not have kernel panic with clean system (especially .2 version) unless there is something wrong. iMac is telling you something this way.
You could try wipe and install older system (they can be downloaded from Apple) - it is possible prior system may be more forgiving to whatever is going on with this iMac. But something is out of spec. If there are logs to this kernel panic, someone smarter than me might be able to tell you which part of system is causing it.

Thank you Honza1. I would certainly like to go back to Catalina. Big Sur has been nothing but problems for me. I have been trying to find a way to reinstall Catalina but have not found it yet. It doesn't seem to be in the app store. I have read the panic kernel but of course it doesn't make any sense to me. Tried to copy it but regular right click doesn't seem to work on it. Then again right click isn't working on the icons in the task bar either, it just opens the program, doesn't give you the option to remove from taskbar. So many weird little things since this update. It also has trouble finding my mouse at times. I also have a strange new internal disk ST2000DM001 media that keeps giving me an error that it is uninitialized. Not sure what that is and can't find a way to initialize it even though I click on that option in the error message..

 

[Honza1]

Read this and try links from there:

How to Download Full MacOS Installers the Easy Way with MDS

Downloading complete macOS installers has long been possible via the App Store and the command line, but some users encounter difficulties with those approaches, or find them too cumbersome. Anothe…

osxdaily.com

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com

and if you search support.apple.com for exact version installer dmg you want, you will find it: "10.15.7 Combo Update" will find https://support.apple.com/kb/DL2052?viewlocale=en_US&locale=en_US which has button to download the 5GB installer dmg.