Unable to load game.

i try to play a game today and every time i tried to load my game it would crash instantly and give me a bugsplat error. can anyone tell me why this is happening please? this is not the first time this happens to me. it happened when azir came out about 3 games in a row and i couldn't play for a week. it stopped happening and i could play peacefully but now it started happening again. im playing on mac os. please fix this soon riot,its getting really frustrating.