In 5.2.1f1 Editor freezes in play mode

Game works fine on 5.1.3f.
In 5.2.1f1 it works for between 30 seconds and a few minutes, then just locks with beach-ball.
I have to force quit unity after that. No crash report etc.

Unity Pro running on OSX 1.9.5.

After further testing, it was my code that was doing it. Just didnt realize it since unity didnt show any errors. Crazy what one line of code can change in performance.

i dont even have any code in there and it freezes one minute after hitting the play button, bur i have particle animations could it be that something is wrong with those particles ?