SPOILER WARNING: If you have not yet completed Diablo III on Normal, some issues described in this list may include spoilers.
If your Hotcorners stop working:
1. Go into System Preferences>Desktop & Screensaver.
2. Disable all hotcorners and save the changes.
3. Re-enable your hotcorners.
Workaround: Go to your system preferences and unselect and reselect your output device after installation.
Update: Our team is working on an upcoming optimization updates that improves performance for Mac clients, for more information about this, please read here.
Workaround: Exit Diablo III and fully patch your game. Your cinematics should play fine then.
Workaround: Exit Diablo III before changing Parental Controls.
Workaround: Leave the game and create a new one, or don't kite monsters to Scoundrel' spawning area.