I have noticed having problems with WBFS freezing up too on a ISO copy or even a HDD to HDD copy. But I've also found that if you just wait it out, it will eventually come back. At least this has been the case for me multiple times. I have no explanation for this. I was doing an HDD to HDD backup and it kept freezing over and over again. So I said %*$& it and went to bed. When I woke up in the morning, the drive had completely finished copying though, so it must have worked. I don't exactly consider it patience... but the end result was the same!