Gmod won't launch (correctly)

Steam pops up the starting gmod window, but when it fades away like when it would normally just before launch, nothing happens. Tried restarting steam several times, using the desktop shortcut, from my games list, etc.

Any idea what’s causing this?

Restarting your computer sometimes helps.
I used to have the same problem with ‘Spore.’

Is TF2 mounted?

Stick this in launch options


-fullscreen

Try adding -width 800 -height 600 to the launch options as well

Restarting DID fix it, surprisingly. Thanks.