Corruption in Installation?

I opened League and it says that there was corruption in installation...

It says: "Sorry! We've detected some possible data corruption in your installation. Would you like to repair the corrupted files?"

They have two options which is "ok" and "quit". I clicked OK and it began to update. I exited and reopened the client and the same message appeared. I clicked quit and it didn't update and was fine... I've had League since Nov 2014 and have never had a problem like this before. So I clicked "OK" again this time and I'm going to see what happens if I leave it to update. I searched it up and this came up: http://forums.na.leagueoflegends.com/board/showthread.php?t=4269466