Engin Error. Please HELP!

Yesterday on Saturday, November 1st, Garry’s Mod was working just fine. Today when I was launching the game in Steam an Error Message Popped up stating: Engine Error: failed to read 16 bytes. After Pressing OK the game crashes and this repeated whenever I try to launch the game. I have uninstalled and reinstalled the game, went to the source folder and deleted it, and even restarted my computer. None of this has worked. Upon looking online my efforts have been unfruitful.

I am currently using a Macintosh Computer.

If anyone can help it would be much appreciated.

(User was banned for this post ("Wrong section. Read the rules before you post." - postal))