ProTools 12 crashes & freezes

Just started using my new copy of ProTools 12. I tried loading up 2 separate sessions 4 times in a row, and 30 seconds in I get the beach ball and protools doesn't respond. Had to force quit. It also crashed on me once upon 'loading up' another session with no warning (same problem occurred in 11) This has happened all in the period of an hour. I was able to open a different session however with no problem... so this version just seems a little buggy. I have Yosemite 10.10.3, fully maxed out 2014 MBPro. Apollo 16 tb, soundtoys plugins, uad plugs, waves plugs.