Mac OS League crashing

So I've been getting this occasionally, and it's getting quite annoying now. Every now and then, after a victory or a loss, my game freezes after I press the "Accept" button to return to the lobby. I know it is not my Macbook having a kernel panic because I can still use the quick keys to mute, increase/decrease volume, skip/repeat and pause/play music on iTunes. If I could minimize LoL and bring up Activity Monitor to force quit League I would, but I can't because the screen is frozen on League of Legends.

Is anybody (using Mac OS) experiencing the same problem as I am?