[MAC] Garry's Mod won't run properly!

As stated in the title, Garry’s Mod won’t run anymore;
The first day I got it, I was playing around and experimenting with all the tools (to get a feel for the game), but when I came back the next day, I would launch it on Steam and it would open up GMod, stay on the loading screen for a bit, then exit out and I’d get an error. If I try running it again, GMod simply goes on an infinite load screen and I have to Force Quit the application.
Help?

Error is?

Remove addons and test one by one. Only one i can think of since it’s mac

I don’t have any addons, just barebones Garry’s Mod