[CRASHING] Constant Mac Client Crash -Pls Help-

I decided to get off of league for a while, about 3-4 months, and play other, better games and such I got back on today and all of my friends were excited to see me and so we started up a game. It would load up to 100% percent and then crash. I would then have to reconnect. This happened 3-4 times before i just gave up on it. This was only in teambuilder as i have been reluctant to try any other modes. If anyone has a fix please let me know.

OS: OS X Yosemite 10.10.2