I am finding this with a number of applications, not only Microsoft ones.
Basically some executables will no longer execute, some word documents won't open and some MS access databases won't work.
For me, this all seems to have broken with the 2.2 update.
I don't seem to be able to copy these broken files anywhere else, overwrite them, anything.
Interestingly I have two computers running Boxcryptor, one is running Win 8.1 and having issues, the other is running Win10 and working far better. (Still issues but not this one)