Patch 6.6 Issue (Mac)

I'm not sure if other people have the same problem. After updating to 6.6 (Mac), I can no longer speculate games (the interface will be paused at a black screen somewhere before the champion loading phase). During the black screen phase, I cannot switch back to desktop or any other programs. The only way to solve this was to shut down the computer and restart again...so annoying... Same thing is true when I try a custom game. (Haven't try PVP or PVE yet, probably the same issue). I reinstalled the game once and the problem is still there.