Big Sur install glitch

[Bob Marsden]

Stuck in an eternal loop. Don't know how to evict the damaged copy.

Clicking 'GET' on the App store just sends me to the install option on my iMac, which says it will take 15 minutes, then defaults to Damaged Copy alert. What procedures should I carry out to accomplish the installation?

 

[Lufbrarunner]

Are you installing on top of a previous OS or installing from scratch?

 

[Bob Marsden]

Replacing Catalina.

 

[Lufbrarunner]

Do you have a backup of your 'old' system?
if so it may be easier to wipe the disk, do the install and then restore from the backup

 

[Bob Marsden]

I have Time Machine backups, but I don't trust it to reinstall everything including settings. I'm wary of wiping my current system. Where in the system would the damaged Big Sur file be?