I find that sometimes when I try swiping between desktops while the game is loading something, the game/my computer freezes. My comp isn't too bad, so I only half think it's solely because of outdated hardware. I use a "mid" 2010 macbook pro, with 4 gigs of memory. I run no other programs besides for having google chrome and the blizzard app open when playing. No error codes or anything, my computer just completely freezes (except the mouse). Also, this happens when I try to use the swipe command that makes all the windows and desktops show (4 fingers up).

3 small notes: This only started occurring after the 2.0 update, usually while traveling between places. The music sometimes doesn't stop playing, even while the computer is closed. Also, a technical detail is that i'm usually playing in a room-tempurature place with my fan running and windows open, so it's a reasonable temperature and decent airflow.
As a temporary fix, I find that closing and opening my laptop forces it to become unfrozen (I close it, I open it, it stays frozen, the screen goes black like going to sleep, and then it turns on and is unfrozen). This is probably just a sign that my computer is really slow, but that's pretty much all the details and this is a fairly recent problem.