Hi again, thanks for your continued help.
I think I'm good to go. See detailed notes below. Again, much appreciated!
1) I use Carbonite, Backblaze and Acronis plus (also) iDrive.
2) I removed older Java versions. Did install latest.
3) I removed Bonjour apps.
4) I didn't look at any GUID folders ... no idea what to look for. I'm happy to follow any additional advise you have here.
5) Ran SFC /SCANNOW ... got this:
Beginning system scan. This process will take some time.
Beginning verification phase of system scan.
Verification 100% complete.
Windows Resource Protection found corrupt files and successfully repaired them.
For online repairs, details are included in the CBS log file located at
windir\Logs\CBS\CBS.log. For example C:\Windows\Logs\CBS\CBS.log. For offline
repairs, details are included in the log file provided by the /OFFLOGFILE flag.
6) Ran DISM.exe /Online /Cleanup-image /Restorehealth ... got this:
Deployment Image Servicing and Management tool
Image Version: 10.0.19042.1052
[==========================100.0%==========================] The restore operation completed successfully.
The operation completed successfully.
7) Tried to activate Pro subscription again ... seeming worked!