Crashing on Mac

Basically, over the past two days, my game has crashed in the loading screen three times due to random crashes and I've needed to force quit and reconnect, usually 10+ minutes into the game. More than once, one game has crashed multiple times and I'll try to load in 2 or 3 times, just to crash again and start the process over. This last "defeat" because of the crashing sent me into low priority queue. This has been going on for more than a year, and I've tried repairing the client several times with no luck. One game took 18 minutes to reconnect, and when I finally got back, I was disconnected again because the game thought I was just AFK. I don't get ant leeway in the form of a loss prevented when I crash, and there aren't any signs beforehand so I know when the game will crash. I'm totally sick of having this happen, especially during Party IP Week, because now I don't have any friends that are willing to wait 10 minutes extra for a game and/or aren't willing to risk playing with someone prone to crashing. If you have any tips on how I can fix this, I would greatly appreciate them. I've read other post about this problem, and it seems to be exclusive to the Mac client. I load slow normally, which make the whole process practically unbearable, because I know I'm gonna get flamed by my team and punished by LeaverBuster for something I have no way of fixing. PLEASE HELP!!!