Just adding:  I've done all of the rebuild/repair things to my system, many times over.  I've upgraded several times, no resolution.  The issue persists.  I'm beginning to wonder if it gets broken every year when we have to turn off certain inventory things so that we can produce an accountant's copy.  Things handled within the same year seem to go along fine until we have to do that...then it falls apart it seems.  (Of course, this takes years to test out.)  Any clue if this is breaking something related to serial numbers on hand, decrementing them from inventory, etc.?