I think WindowsUpdate was interrupted on the way to completion.
Would you try to check the integrity of Windows system?
1. Open PowerShell with Administrator previledge
Right-click Windows icon on the lower-left of screen and click “Windows PowerShell (Admin)”.
Then PowerShell runs.
2. Check filesystem
In PowerShell, execute
chkdsk c: /f /x
Restart your PC. Disk check will start. I hope the success of the check.
3. Check the Integrity of Windows system
Open PowerShell (Admin) and execute
dism /Online /Cleanup-Image /CheckHealth
dism /Online /Cleanup-Image /ScanHealth
If any errors happen, execute
dism /Online /Cleanup-Image /RestoreHealth
sfc /scannow
If done successfully, restart PC.
If any errors happen here, I think reinstall of Windows is needed.
4. Clear temporary files
Open PowerShell (Admin) and execute
cleanmgr /d C: /VERYLOWDISK
Then, restart PC.
NOTE: WindowsUpdate sometime uses a few tens gigabyte storage to work. Preserve enough free disk space.
After all above, try to enable WindowsUpdate.
(I recommend that “fast startup” mode is disabled. See Standby issue hi10 x - #33 by EndlessBiginner)