Not saying this is what's definitively happened but, asking you to entertain the idea that it's plausible.  It may just be taking a while to process stuff.  On my wallet it has hung or seemingly hung for more than just a few seconds.  However, it didn't crash.  Even the "(Not Responding)" thingy showed up in Task Manager.  I came back more than ten seconds later and all was fine.

I have had several instances where the synchronization progress bar just sat there for more than a few seconds.  Giving the appearance that it crashed.  But it didn't.  Wallet version 2.0.4  on a 4th gen core i5 based system.  I set the number of script verification threads to 2, rather leaving it at what it defaulted to for me of 4.  I'm not entirely sure what that setting does but, it is something I changed.  I don't want to burn all 4 cores on just the wallet(I've got 4 cores and no hyperthreading).

I do wonder if some of the whackiness I've seen is from being behind a second firewall after a main one.  I swapped the subnet masks out to change the classes and I'm in the realm of 'unsupported' configurations according to the ISP.  But everything seems to work.  I do wonder and imagine that the latency has gone up however.