GMOD 13 doesn't load to the menu?

Whenever I start GMOD 13, it only shows the menu background, and that’s it. It then crashes.

What’s the deal here? It seems it started after I replace the gmod folders with backup ones…

UPDATE: I’ve seen some posts instructing to clean out the “garrysmodbeta” folder. Should I clean it out? The game ran fine without it.