Startup Glitch (Mac)

I’m on a mac (10.9), and whenever I try to launch Garry’s Mod, is comes up with this (I think it might be the Mavericks):

Couldn’t load: \Users(user)\Library\Application Support\Steam\SteamApps\common\GarrysMod\garrysmod\bin\client.dylib
Reason: dlopen(\Users(user)\Library\Application Support\Steam\SteamApps\common\GarrysMod\garrysmod\bin\client.dylib, 2): image not found

And after that it doesn’t load and when I try to reload the game it makes me update it, and then repeat the process. Also, I have tried re-installing the game.
Any way to fix this?

Switch to the Dev Branch.