Jordan Johnston wrote:
You can do 3 things,
Reset your computer, it could be just a error in your system.
Validate Game Cache Steam > Steam Library > Garry's Mod > Right Click >Properties > Local Files > Validate Game Cache.
Check your addons,
I validated it and had 8 failed files that were re-acquired, but it did nit solve the problem. What do I need to check in my add-ons?