CS:S and HL2 Content in GMod Maps: What Players Have

A GMod map can rely on the content of GMod itself, on Half-Life 2 and, since the July 2025 update, also on most of the textures, models and sounds from Counter-Strike: Source and the Half-Life 2 episodes. GMod ships these packages, so nobody has to own another game for them. The maps of those games, their voice-over and their music are not included. Content from other games such as Team Fortress 2 or Portal is only available to players who have installed the game and mounted it in GMod.

What ships with GMod itself

Besides garrysmod.vpk, GMod's gameinfo.txt names four packages from Half-Life 2: hl2_textures, hl2_misc, hl2_sound_misc and hl2_sound_vo_english. A current installation also has content_cstrike and content_hl2 in the sourceengine folder. Facepunch introduced them with the July 2025 update: since then most of the content from Counter-Strike: Source and the Half-Life 2 episodes is part of the game, with permission from Valve according to the announcement. Maps, voice-over and music are excluded, the last two for licensing reasons.

Many older guides still advise buying and mounting Counter-Strike: Source. For textures and models, that is outdated in most cases since this update. Facepunch itself writes that it does not eliminate every case of missing content.

How mounting works

Mounting means that GMod adds the folders of another installed game to its search paths. Its materials, models and sounds are then available as if they were in the game folder.

Players do this in the main menu: the bar along the bottom edge has a gamepad icon on the right, labelled "Games". The list shows every game GMod can mount. Only installed games have a checkbox, the others are marked "Not Owned" or "Not Installed". Merely owning a game is not enough.

A dedicated server has no menu. There you enter the game's folder in garrysmod/cfg/mount.cfg:

"mountcfg"
{
	"tf"	"C:\mytf2server\tf"
}

The folder has to contain _dir.vpk files or the usual subfolders such as models and materials, and the path ends without a slash. Which installed games GMod tries to mount on its own is controlled by the file mountdepots.txt in the same folder. According to the GMod wiki, mount.cfg also applies to Hammer and the compile tools.

What players see when content is missing

A missing material appears as a pink and black checkerboard, a missing model as a red ERROR. Missing sounds simply stay silent. The cases and their fixes are covered in fixing missing textures and ERROR models.

The server having the content mounted does not help the players. Every client loads materials and models from its own search paths, and mount.cfg only extends the server's file system. The server needs the content for itself, for example so that entities and models from that game work at all. It only transfers to players what it offers for download: the map with its packed files, files via FastDL and Workshop addons. How these routes work is explained in installing a GMod map on a server with FastDL and Workshop.

The options for mappers

1. Avoid it. If you stick to GMod, Half-Life 2 and the bundled content from CS:S and the episodes, every player sees the map in full. Leave out music and voice-over from CS:S and the episodes, because they are missing from the bundled package.
2. State the requirement clearly. If you use content from Team Fortress 2, Portal or another game, write in the description which game has to be installed and mounted.
3. Pack what you are allowed to pack. Your own content and third-party content with a suitable licence belong in the BSP. The procedure is described in packing custom content into the BSP.

Content from Valve games does not fall under point 3. The Steam Subscriber Agreement prohibits copying or distributing content without Valve's prior written consent, unless the agreement itself or applicable law permits it. GMod's Workshop rules are more specific still: addons containing content from a paid game are removed, with CS:S, Portal and the Half-Life 2 games named as examples, and this explicitly includes props an addon needs in order to work. The announcement from Facepunch mentions Valve's permission only for shipping the content with GMod. It says nothing about mappers passing it on with their maps. This is a reading of the published terms and not legal advice. The basics are in GMod map copyright basics.

Checking which assets a map uses

1. Textures in Hammer. Tick "Only used textures" in the Texture Browser. The folder names hint at the origin: de_dust, de_nuke or cs_italy are in the CS:S package.
2. Models in Hammer. Open Map > Entity Report... and filter with "By key/value" for the key model. Paths such as models/props/de_inferno/ or models/props/cs_office/ come from CS:S, models/props_mining/ and models/props_silo/ from the episodes.
3. Packed files. bspzip -dir yourmap.bsp lists the contents of the pakfile. The Map Scanner also lists embedded Lua and asset files in the pakfile. Both show what the map brings along, not what it expects on the player's side.
4. The test that counts. Untick everything in the "Games" menu, take your own entries out of mount.cfg, disable your addons and load the map. That shows it as a player with nothing but GMod sees it. The console command path shows which search paths are currently active.

Hammer itself is not a test. The editor finds everything that exists or is mounted on your machine.

What server owners should tell their players

• Name the required game explicitly, in the server description, on the loading screen and wherever new players ask first.
• Explain the route in one sentence: install the game through Steam, tick it under "Games" in GMod.
• Link your Workshop collection for addon content so players do not have to hunt things down one by one.
• Do not offer packages with content from Valve games for download. The Workshop rule above also covers content packs for servers, and the Subscriber Agreement applies to every Steam account.
• Check on your server whether the files content_cstrike_dir.vpk and content_hl2_dir.vpk exist in the sourceengine folder. In the game installation they do. At least one hosting provider reports the same for the dedicated server, but the announcement from Facepunch does not mention servers. If the files are missing, mount CS:S via mount.cfg as before.

Before you buy a map, find out which games it requires. Every additional game is a hurdle for new players. The other pre-purchase checks are in buying GMod maps safely.

FAQ

Do I still need Counter-Strike: Source for GMod?

Not for most community maps any more. GMod has shipped most of the textures, models and sounds from CS:S since July 2025. You still need the game if you want to load the original CS:S maps or if a map uses its music or voice-over.

Why do some players still see checkerboard textures?

Then something else is usually missing: the mapper's own content that was not packed, an addon from the server or content from a game that GMod does not ship. Facepunch also writes that the update does not eliminate every case.

How do I notice missing sounds?

Less easily than missing textures, because a missing sound produces no visible sign. During the test without mounted games, listen specifically for music and voice lines. Those two kinds are exactly what the bundled CS:S and episode package lacks.

Does Hammer see the same content as the players?

No. Hammer shows what exists and is mounted on your machine, including the entries in mount.cfg. Only the test with the games unticked and without addons shows whether a player without additional games sees the map in full.