Crash(loading screen black)

every time i join a game after champion select my loading screen goes black and i cant join back into the game in-till i reopen my client many times.I re downloaded the game thinking that it would stop but it didn't and i don't know why this is happening.It started happening ever since this new patch came out and i cant do anything about it and now i get reported all the time cause im afk or i join in to late.Someone Please help