I found a fix
I use CA Security suite and after the latest updates from Microsoft my CA antivirus
kept finding a problem with shell32.exe. This was an error, the virus signature dat for some
reason identified shell32.exe as a threat after the updates. To fix this I:
restarted in safe mode
set exclusion for \windows\system32\shell32.dll in CAAV options panel for Real Time and On Demand
virus checks.
Once excluded from Quarintine a re-boot and all was well.
Also on a second machine, I
restarted in safe mode
Updated the CA dat files and all worked.
Hope this helps. Maybe more antivirus programs see the updated Shell32.exe as a threat and are
blocking it.