I bought Garry’s Mod on a new Steam account. My other Steam account has CS:S, TF2, HL, etc installed. How could I use those textures on this account so I don’t get errors?
Drag and drop the CSS folders (materials,models,sound) in to a new folder (csscontent). Then drop the folder (csscontent) in your gmod addons folder (C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod\addons). Then install TF2 on your steam account. HL/HL2/HL2EO/HL2ET is NOT required i think.
That account that has Gmod needs to also have CSS on the account and installed as well as all other content needed.
That method that is posted is shady and does not work 100% of the time.