Client keeps crashing during logging in

Whenever I log in and before I even type down my user and password, there's something that always pop-ups saying "We have restored this installation to an older version of League of Legends. Now we'll try to patch it up to the latest version" and the only option that shows there is "Okay." So I click the 'Okay' button and it'll show another pop-up saying that it requires a little update so my client will have to restart and patch. After clicking 'Restart now' the client starts to load and once it's done loading it only shows a blank screen of where I log in or "We have restored this installation to an older version..." pops-up again and again. I play on a MacBook Pro and this has never happened to me before. If there's a possible way of solving this problem, I'd be very much appreciate your help!