Garry's mod not working on singleplayer.

So I decided to play a little Gmod today, and when I tried singleplayer, it loaded up, and returned me straight to the main menu, I tried maybe 5 times before giving up. I then tried multiplayer. It loaded up, and worked all fine, no issues at all. I deleted and reinstalled Gmod and the same thing happens. Any advice?

Someone else had a similar problem. Here’s the thread http://forum.facepunch.com/showthread.php?t=1230976&p=38754392#post38754392 . This wouldn’t work for me because I use mac, hope it helps.

Yup, disable your workshop addons, all of them. Turn them one by one to determine which addons is causing it, and remove it.