Patcher not offering repair option... anyone else?

So I just installed Windows 8.1 on my computer. I load into League, start into a Co-Op vs. AI game to practice Zed, and as the client is trying to connect, I get an error saying that I don't have a file that I need. I go into the patcher to repair League, but the repair button is missing. Has anyone else had this issue since 5.1? If so, how do you solve it?