The problem is that we don't know why this is hapening.
We never got a clear answer from Avast! on this.
What we do know is, that it is a problem with MBAM Premium, and NOT with MBAM Free.
Also that what I posted in Reply #12 has helped some users.
What you could try is to exclude the Avast! program folder in MBAM ( I have never tested that ):
Go to : MBAM - Settings - Malware Exclusions - Add Folder ... and select :
C:\Program Files\Avast Software\Avast
Reset SafeZone and reboot.
That said, in AVAST 2015 R3, that is planned to be released ~ June/July, the Sandbox and SafeZone will be completely rewritten.
So than this issue could be solved ( or not ... ).
Greetz, Red.