Purple textures and big red flashing errors in gmod are usually caused by you not having Counter-Strike: Source. A lot of mappers use materials and props from that game.

There are two ways to fix these errors.

One is paid, and is very easy
The other is free, but requires more effort

I will go over the paid one first, since its simple.

The easiest way to fix the textures is to actually buy the game.

https://steamhost.cn/app/240/CounterStrike_Source/?t=The easiest way to fix gmod textures!

Just download it, and restart gmod. Gmod should then automatically pick it up and start using it.

This method is a little more complex, but shouldent be too bad.

Steps:

1. Go here:
   
   
   
2. Click GarryContent (right side of the screen)
   
3. Scroll down to Counter Strike: Source
   
4. Click MEGA Game content (the red button)
   
5. Click SKIP AD after a few seconds (DO NOT click anything other than skip ad on this page.)
   
6. Click the big red DOWNLOAD button (or download from browser button if the button wants you to install a chrome extension)
   
   
7. While its downloading, go to your library on steam
   
8. Right click gmod and click properties
   
9. Go to Local Game Files
   
10. Click Browse local game files
    
11. Open the folder called garrysmod
    
12. Then open the addons folder
    
    
13. Once the file is downloaded, extract it and drag it into the addons folder
    
14. make sure that folder has folders inside it like materials, models etc
    
    
15. Restart gmod

That's it!

That's how you fix the purple textures and errors on gmod!

If you had any issues, please join my discord server[discord.gg] for support.
NOTE: Before you join my discord server, please read every word around the area you are having trouble with.