Being not so great on linux I was trying to avoid problems by following the step-by-step instructions on the wiki page at https://pve.proxmox.com/wiki/Upgrade_from_7_to_8
I'm replacing my old server with a new one so to make sure things go smoothly I decided to do an installation on my old backup server first. So following the instructions for a New Installation I discovered (too late) that the files we're told to restore in steps 6 and 7 are NOT the same as the files we were told to backup in step 2. Since step 3 wipes out all the files on the computer there is no way to go backwards and get the files that step 6 and 7 are telling you to restore. They've already been destroyed in step 3.
I'm replacing my old server with a new one so to make sure things go smoothly I decided to do an installation on my old backup server first. So following the instructions for a New Installation I discovered (too late) that the files we're told to restore in steps 6 and 7 are NOT the same as the files we were told to backup in step 2. Since step 3 wipes out all the files on the computer there is no way to go backwards and get the files that step 6 and 7 are telling you to restore. They've already been destroyed in step 3.