[CLIENT] [CRASH] Game freezes 2-3 times per game and reinstalling game causes constant crashes

So, I had no trouble with the game until today where the three games I played all had me freezing 2-3 times per game, I have no idea why or how but I was in Skype at the time and I was still heard in it I just had no control and the screen was completely frozen. I tried to repair but the client kept crashing when I initiated that, so I uninstalled the game and reinstalled it and it's giving me a similar problem to this. I would greatly appreciate and idea or solutions to fixing this problem, Thanks.

Edit: I realise I should point out this is on a Mac

Update: I have been unable to get past 33% in the install as it will progress a few percentage and then crash.