Oh, I use the following for protection too:
- Cybereason Ransomfree (to protect from ransomware)
- Sandboxie (to run apps in a sandbox)
- Panda USB Vaccine (to protect from infected USB sticks)
Could it be any of the above that causes the problem?
I suspect the Cybereason Ransomfree, but on the other hand I use it for couple of years now without problems of this nature.