iMac 2017 Retina OS install woes

[Cameront9]

I have a 5K Retina iMac from 2017 that is stuck on Catalina. I believe it has a Fusion drive. Every time I have tried to update it (first to Big Sur and then Monterey), it has entered a boot loop during the update process that requires a complete restore from a Time Machine backup. The upgrade cannot proceed. I have yet to try Ventura for fear that the same thing will happen.

Has anyone else experienced this? Any remedies? I guess I could always install on an external drive and boot from there, but I'd rather not do that. I'm assuming this might be related to the 2TB Fusion Drive since those are a PITA.

 

[CoastalOR]

Have you talked to Apple Support?

Have you tried using Disk Utility to repair your drive?

How much free drive space do you have?

Here are suggestions from Apple:

If an error occurred while updating or installing macOS - Apple Support

The message might say that an error occurred while downloading, preparing, or installing, or that the software is damaged, could not be verified, failed to personalize, or needs to be reinstalled.

support.apple.com

 

[Fishrrman]

As Coastal says above, use disk utility's "first aid" to check the health of the fusion drive.

If nothing else works, what you might consider doing is:
a. MAKE SURE THE IMAC IS BACKED UP
b. Boot to INTERNET recovery (command-OPTION-R)
c. Use disk utility to ERASE the fusion drive (be sure to go to the view menu and "show all devices" first)
d. Install a fresh copy of the OS onto the "empty" drive
e. RESTORE your data from the backup.

But again, YOU MUST HAVE A CURRENT BACKUP to do this.