Guide for fixing workshop errors/missing materials related to the workshop

A quite common issue these past few years is workshop addons not being downloaded properly. This goes for both server-side workshop addons that are on autodl and workshop addons that you are subscribed to.

And how does this problem manifest itself?

Mainly you will know that you have the problem if you are:
  • Unable to download workshop addons that you are subscribing to
  • Unable to autodl workshop content from servers (see a lot of errors and missing materials as you join)
  • Players or other server content (not map content) are errors or are missing materials and you cannot see it even after restarting Garry’s Mod.
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Stuck "Updating" Workshop Content - Ask SF-O - StarFox-Online

 Errormessages in the gmod console
WorkshopDL: Failed to read addon file for ‘Gerbil Mountain: Shared Server Pointshop Content’ (1593449308)
Not loading addon ‘addons/resident_evil_-_vector_playermodel_220687225.gma’ – file doesn’t exist Couldn’t mount addon [Resident Evil – Vector Playermodel][addons/resident_evil_-_vector_playermodel_220687225.gma] Removing bad addon addons/resident_evil_-_vector_playermodel_220687225.gma

Is there a guaranteed solution?

Quickfixes
  • Try restarting Garry’s Mod and see if the issue persists. Often Garry’s Mod fails to load new workshop addons are loaded as you join the server, and as such; you need to restart Garry’s Mod to make sure that they are mounted properly.
  • Verify the integrity of your Garry’s Mod Installation. For some, this has solved the problem
 FIX: Delete your cached/downloaded data and clear the workshop cache
  • Shut down Garry’s Mod
  • Navigate to your Steamapps folder (Steam\steamapps)
  • Delete the Downloading folder
  • Go into Workshop/content and delete the folder called 4000
  • Go back one step and delete the folder called downloads along with the appworkshop_4000 file and temp folder.
  • Navigate to your Garrysmod folder (Steam\steamapps\common\GarrysMod\garrysmod)
  • Open the Cache folder and delete the DownloadCache.db file, along with the Workshop and Lua folders.
  • Go back to your Garrysmod folder and navigate to downloads (not download) and clear the folder of all the files
  • Open Steam, Click on Settings and go to the Downloads tab and click on the button marked below. You will be signed out of steam and will need to sign in again. If this does not solve it, go to the next fix.
 FIX: Reinstall Garry’s Mod
  • Shut down Garry’s Mod
  • Back up any files that you may have saved under the GarrysMod folder (Steam\steamapps\common\GarrysMod\garrysmod)
  • Right-click Garry’s Mod in steam and click on Properties
  • Navigate to the Local Files tab and Uninstall the game.
  • Once done, navigate to Steam\steamapps\common and delete the GarrysMod folder
  • Install the game anew