Hello Abelh can you give me the content in file:
C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod\data\zmod_global_options\pcolora.txt
C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod\data\zmod_global_options\pcolorb.txt
C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod\data\zmod_global_options\pcolorc.txt
Me I have by exemple in:
pcolora.txt=255
pcolorb.txt=0
pcolorc.txt=150
That can help me. To fix this problem.
To fix it you have just need delete this 3 file.