Hi Nigel,
try running the update troubleshooter:
Link Removed
Run these scans just to make sure the system isn't corrupted.
File scans
Right click on the Start menu icon and from the revealed list choose 'admin command prompt'. Type:
sfc /scannow
press enter and await results
In the same command prompt and after the above scan has finished type:
dism /online /cleanup-image /restorehealth
Press enter and await results (longer this time).
Check for malware:
Free Anti-Malware & Internet Security Software
Rebuild the index:
This guide was originally for win 7 but it still works for win 10.
To rebuild the index
The index requires almost no maintenance. However, if the index can't find a file that you know...