Same error I got too. I just reinstalled Win 11 to get it over with. Most files were retained, but I built a backup in OneDrive.
Thanks for your reply. I've been thinking I should do the same.
I'm a tad paranoid about saving my data to the cloud, but have a 5 Terabyte network hard drive that should suffice, plus a couple of extra portable HDD, so I'll back up files.
Was there anything the missing files had in common, or was the data loss covered by the backup you made?