Missing content
When distributing a map or mod, care must be taken to ensure that any custom content (sounds, materials, textures, models, etc.) is also distributed, or else players will have an unintended experience.
- Missing materials/textures show up as a black-and-magenta checkerboard (in Counter-Strike 2, shows up as black-and-red checkerboard that flashing, and Half-Life: Alyx shows up as red wireframe that flashes).
- Missing models show up as red 3D text saying "Error" (in Portal 2 the 3D Error text is a light blue, in CS:GO since new updates shows up as big red box with ERROR text textured on it, and Source 2 and Strata Source games shows the text in orange color, with Source 2 games being in a slightly different font)
- Missing sounds are absent (in Portal 2, a missing sound is indicated by Dr. Kleiner saying "Oh, fiddlesticks. What now?", and CS:GO, a klaxon sound plays.)
- Missing particles (at least in Portal 2 and Team Fortress 2) appear as a spray of red X's.
If the missing contents shipped with the Source SDK, and are not custom creations, it is likely a problem with your game configuration. See Reset the Source SDK Game Configuration for more information.
Common Problems
One very common problem is when users see a black-and-magenta checkerboard/black textured "sheen" or reflection on surfaces. This is caused by a missing texture, generally due to missing cubemaps, which must be "built" in-game prior to distributing the map.