Method 1 - The Game
This is the preferred method if you either own or have the ability to purchase the game.
Counter Strike: Source is a game that GMod more specifically DarkRP utilizes a lot for its models, textures, etc.
All you would need to do in purchase the game -
Install the game and restart GMod, just like that all textures CS:S related are fixed. No more purple and black squares.

Method 2 - Free

This Method only works on Windows
1 - Goto
2 - Download Counter Strike: Source Game Content
Downloading Content
3 - Open the .zip and locate your addons folder
Steam Library
Steam Properties
GMod Directory
Addons Folder
4 - Drag and Drop the content folder in the addons folder

Purple and black squares, missing textures, cannot see map.
Was this article helpful?
Thank you!