Black Screen?

I'm running League on a Macbook Pro using OS X El Capitan. For the past couple months, I have been able to play League perfectly EXCEPT for post game. After I have finished a game (every time) there are no post game stats that show up. My entire client goes black except for my friends, notifications, clubs and the top bar with my information. I am able to accept game invites; however, am unable to actually accept anything due to the black screen. Because of lack of the "Play" button post game, I am unable to go immediately into another game and am forced to close League out every time I finish a game. I am not able to see summoner names, the honor buttons, add, etc, the entire screen just goes black (except for the few things mentioned). Has anyone run into this problem on a Macbook? Are there any temporary/permanent fixes? I sent a ticket into Riot and they told me to restart my computer or log out of the client. I did both of those things along with completely reinstalling the application, but it is still doing it. Literally anything might help!

Side Note: My boyfriend is able to log into his account perfectly AND plays on the same computer as I do. He does not have the post game problems at all and neither does my test account (for figuring out if it was only my account). It is only my main account that has this problem.