[CLIENT] Whenever I edit masteries and click save, client freezes

Whenever I edit masteries, and click save, client freezes. I'm still able to go into game, but I can no longer change runes/masteries or summoner spells. Every button on the client no longer responds, and the client is "dulled" or "faded" (darker color scheme). After the game is over, the client is still frozen.

This has happened to me in both ARAM & def not dominion. I haven't played any other game types this patch. This is the 3rd time it happened, every time I edit a mastery and try to save.

Posted on reddit about this bug as well:

LINK: https://www.reddit.com/r/leagueoflegends/comments/55zsqe/patch_620_bug_megathread/