Originally a Win7 machine, successfully upgraded to Win10 during the free upgrade period.
According to the update history it appears to have been struggling to install updates since 1703
Have tried clean boot - no change
Have run the troubleshooter (wu170509.diagcab) which always reports finding database corruption and claims to fix it, but on re-running it still reports the same problem.
Have tried using the MediaCreationTool to do an in-place upgrade, but this always fails (no useful error message)
System drive C: has 118GB used, 334GB free
System Reserved partition has 34.5MB in use, 65.4MB free
Is there anything left to try before giving up and doing a complete re-install of Windows, with all the disruption that entails?