A white screen.

Everytime I load into a game, there's a white screen. This appeared after playing the Dark Star game mode. It has persisted and won't go away. I was going to join a call, but I couldn't. I tried full screen mode with no luck either. I use the Mac version. I have tried pressing F3, but it doesn't work anymore. I tried scrolling to change desktops, but that didn't work either.