Bennieboj, have you done an Avast Removable Media Scan of your USB flash drive to make sure it is clean?
I still suggest you download MBAM (see my prior post on how to do it) as an on-demand (when you need it...not resident) scanner. It is compatible with Avast, and tends to pick up things that other AV's don't pick up.
By disabling the shield, as you are doing now, is just a work-around...but not fixing the core problem. I realize you are waiting for the minidump to be analyzed, but in the meantime, you should check to make sure your system is clean.