[6.6] OSX - get through champ select, cannot connect to game. Stuck on black screen after countdown

I updated to 6.6 recently and now cannot enter a new game. I am able to join a lobby and complete Champ Select, but as soon as the countdown finishes the client goest to a black screen and never connects to the game. I have tried to reconnect dozens of times without luck.

I did a program repair from the ? menu on the client, didn't fix it. I've done a clean reinstall, no luck. Anyone else experiencing this or find a fix?