Pink Screen

Recently I started playing League again, after a hiatus of 9 months or so, and I have been experiencing a troublesome bug. Basically, during the game, for no reason, my whole screen turns pink and I have to open my task manager, terminate League, so I can reconnect to the game and keep playing. This has happen in most of my games, around 1 to 2 times. Strangely enough, it only happens in League, not any other game that I play.

Help please.