Warning
Use an administrator account for these steps, and keep a recent backup before making repair or security changes.
What you will achieve
Clear corrupted update caches and restart the Windows Update service stack — last resort before in-place repair.
1) Stop update stack services
Run these in Admin Command Prompt:
net stop wuauserv
net stop bits
net stop cryptsvc
net stop msiserver2) Rename update cache folders
Renaming is safer than deleting because rollback stays possible.
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 catroot2.old3) Start services and run repair scan
net start msiserver
net start cryptsvc
net start bits
net start wuauserv
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow