Left 4 Dead 2 mods come in two kinds: SourceMod and Metamod:Source plugins that run on the server only, and custom content such as campaigns and other add-ons shipped as VPK files.
Back up first. See How to back up and restore your Left 4 Dead 2 world.
Add a mod
- For plugins, turn on Install SourceMod under Settings, then Game Settings, and ask support to apply it. This needs a reinstall, which deletes the server's files by default, including your server.cfg, plugins and settings. Download a backup of the left4dead2 folder first, then put your files back afterwards.
- Upload each plugin file (.smx) into left4dead2/addons/sourcemod/plugins in Files, then restart the server.
- For custom content, upload the VPK files into left4dead2/addons and restart the server; the server mounts them when it starts.
Where files go
Open Files and use these places:
- left4dead2/addons (inside Files)
- left4dead2/addons/sourcemod
- left4dead2/addons/sourcemod/plugins
- left4dead2/addons/sourcemod/configs
Check it worked
Once the server has restarted, read the Console. A mod that loaded shows up during startup, and problems show under Errors and Warnings. See How to use the console and run commands and How to add mods, plugins and modpacks.
If the server stops after you add a mod, remove the newest mod or restore your backup. See How to fix a server that will not start.
