Garry's Mod not launching with "Unknown Error"

http://puu.sh/rTIMO/6c14d12617.png

Started today, not sure why. I’ve tried re-installing the game, restarting my computer, running it with -noworkshop. All to no avail.

Try deleteing your ~/common/garrysmod/ folder and reinstalling completely. Can’t really offer any other help with that vague of an error Steam is providing.

Thanks, it worked.