gmod error going on for years

hey guys i have bean having an error problem for years now i keep getting black and pink boxes and error signs in gmod and i have installed the flowing games
haif life 2
haif life 2 lost coast
team fortress
and counter strike go
please help me thanks and if there are any other games i need to fix this please reply

Do you have them mounted? You can check by clicking the game controller in the bottom right of the main menu. Also, can you provide specific maps where you see this? It could be custom materials/models that are not from any other Source game.

Half-Life 2 is pointless, it can only be used for the maps.

Lost Coast has next to no models/materials/maps and nobody uses them, so its also pointless.

CS:GO is not a valid replacement for CS:S.

Most servers/maps use content specifically from CS:S. Content that is not present in CS:GO.

did i say go i ment i have counter strike source

Half Life Episode 1 and 2.
Just wait for them to come on special.