Catalina Upgrade failed, iMac won't boot - Ongoing Investigation

[absente]

Timeline:

1) Downloaded Catalina update (for Mojave)
2) Installing, computer did a restart with more installing
3) Catalina Screen saying "Cannot find Startup drive"

I then did a manual restart, same error message. Since it seemed like an efi/boot problem I tried resetting PRAM etc first - didn't help. Then to recovery mode, had a look at the disk via disk utility - shows the macintosh hd as unmounted - cannot mount. Did the regular disk check steps, repair of course failed - disk utility saying i should backup the disk.

From there i did a fsck and the disk showed no problems at all. Decided to do a restart again, this time the Catalina screen said that it cannot find the installer. Tried internet recovery, but won't let me pick macintosh hd as an installation location because its "locked".

After spending another 12 hours trying the usual methods we all know about to somehow get my Mac going (without doing a format and losing all my files) I gave Diskwarrior a shot via bootable usb.

After letting it run for two hours it showed me 80 disk malfunctions, yet finished and I am not in the process of recovering my files. The weird part is, that my harddrive had no "malfunctions" before the upgrade.

The question is, what should I do next? I suppose that recovery won't let me choose this disk again, or I might get lucky and diskwarrior actually fixed that. Which however still doesn't answer why all of this happened. I suppose it has something to do with the free space - I've had just 20GB, maybe that could be the reason.

Anyway, I just leave this topic out here, just in case.

iMac late 2013, 1TB

 

[MisterMark]

The question is, what should I do next?

Replace the drive. It is dying.

 

[IowaLynn]

"without doing a format and losing all my files"

Rule #1: never let this be you.

Always do full backup and clone before beginning an update. Esp. a full OS upgrade with firmware and APFS

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

How to Fix 'macOS Could Not Be Installed on Your Computer' Error

The "macOS could not be installed on your computer" error is one of the scariest ones you can encounter, but all is not lost if you see it.

www.lifewire.com

Working with APFS Volume Groups | Bombich Software

bombich.com

 

[Fishrrman]

OP wrote:
"Tried internet recovery, but won't let me pick macintosh hd as an installation location because its "locked"."

Try internet recovery one more time.
But this time, take these extra steps.

When you get to the Mac utilities menu (in internet recovery), do this:
1. open disk utility
2. go to the "view" menu and choose "show all devices"
3. you should now see the "topmost line" that represents your physical hard drive
4. choose to ERASE IT to APFS, GUID partition format
5. does disk utility erase it successfully?
6. good... now close disk utility, open the os installer, and try again.

And YOU HAD BETTER BE BACKED UP before you do this, because it's going to wipe out the internal drive and start over from scratch.

 

[absente]

It's still backing up, 70% left - damn slow but better than loosing my files. @Fishrrman I'l try your suggestion once the backup is finished.

 

[CoastalOR]

Timeline:

1) Downloaded Catalina update (for Mojave)

I gave Diskwarrior a shot via bootable usb.
After letting it run for two hours it showed me 80 disk malfunctions, yet finished

I am confused. Mojave & Catalina both use APFS disk format. Disk Warrior does not support APFS so I do not understand how you were able to use it to find problems. Did you just use it to check hardware and not for Directory repair?

 

[DeltaMac]

Sounds like the Catalina install must have tried (and failed) to make the changeover to APFS, compounded by adding another volume (the - data volume), probably borking the directory.
That's probably why all the errors were found by Disk Warrior - which, as mentioned by CoastalOR, can't repair APFS volumes yet (Alsoft continues to state that APFS volumes are not supported), and is mostly useless for that, so far.

Best choice going forward? Replace the 1TB spinning hard drive (it's likely near failure), installing an SSD.
And, contributing to your problem (from your first post), starting with only 20GB of free space on a 1TB drive. That absolutely worked against your task of upgrading the system.

 

[absente]

2 week update

I still use the same (spinning) disk without any issues. Catalina is stable but awfully slow and buggy. At least the last update seems to have solved some weird 'screen imprinting' issue I had with Mojave as well. I don't know how they came up with Catalina, but they've might have called it Cataclysm instead. Anyway, thats off topic.

I am monitoring the disk daily, ill post an update again if it dies or if there are any other issues.
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I am confused. Mojave & Catalina both use APFS disk format. Disk Warrior does not support APFS so I do not understand how you were able to use it to find problems. Did you just use it to check hardware and not for Directory repair?

I've made the USB installer on my other machine running High Sierra. When booting up (CMD+R) I simply selected "Disk Warrior" from the menu and it started examining the disk by itself. I was surprised as well, but it worked for some reason - so if someone is in a similar situation at some point give it a shot.

 

[DeltaMac]

Just checked at the Alsoft/DiskWarrior support page...

DiskWarrior 5.3 & APFS — ALSOFT

www.alsoft.com

The latest version of DiskWarrior (v5.2) is compatible with Catalina. It can rebuild any non-booted drive formatted as Mac OS Extended (HFS+). DW 5.2 can boot with a Catalina system. It can report on internal drives (I suppose that's what you saw)
It can NOT rebuild APFS volumes (yet). The support article goes on to to say that rebuild capability will be in the next major release of DiskWarrior. There is no time-line posted for that release.


So, unless you somehow located a DiskWarrior newer than version 5.2, then a scan that you might have seen on a HPFS-format drive would be meaningless, as DW can't rebuild that drive yet.

 

[absente]

So, unless you somehow located a DiskWarrior newer than version 5.2, then a scan that you might have seen on a HPFS-format drive would be meaningless, as DW can't rebuild that drive yet.

No, i just checked - I did use the 5.2 version. The scan might have been meaningless, but for whatever reason it a) made my drive visible and b) allowed me to backup my files - and it showed me over 80 disk malfunctions. So in some way or another it solved my problem.