Garry's Mod: change gamemode and mapFrom Sandbox to TTT, DarkRP or Prop Hunt

Published on September 2, 2026 · last updated on November 3, 2026

Two settings are enough

At startup, the server receives two pieces of information: which gamemode is to run and which map it starts with. You set both in your server's startup parameters - unlike much else, they are not in the server.cfg.

It is important that both fit together: Trouble in Terrorist Town needs a TTT map, Prop Hunt a suitable hiding map, DarkRP an RP map. A round-based mode on a Sandbox map does start, but it does not make for a sensible game.

The common gamemodes

Sandbox is already there. All others are added as addons - most easily via a Workshop collection in which the gamemode and matching maps sit together.

Switching in four steps

1. Provide the gamemode and maps. Via the collection or by uploading into the addons folder.
2. Stop the server.
3. Adjust the startup parameters. Enter gamemode and start map.
4. Start and follow along in the console. If the gamemode is missing, the server reports it at startup.

After switching, it is worth looking at the configuration of the respective gamemode: TTT and DarkRP bring their own settings that are independent of the server.cfg - for DarkRP, described in set up DarkRP.

Maps and map rotation

The start map is only the beginning. For round-based modes such as TTT or Prop Hunt, a rotation is worthwhile: after every round, the server switches to the next map, which creates variety without anyone having to intervene.

A word of warning: every additional map is a download for new players and quickly several hundred megabytes. Without FastDL, a large rotation becomes a test of patience. Five to eight well-chosen maps are usually better than thirty.

Several gamemodes on one server?

A server runs exactly one gamemode at a time. If you want to alternate between TTT and Prop Hunt, you have two options:

• Switch and restart. Takes two minutes and is entirely sufficient for fixed groups.
• Run two servers. Sensible from the point at which both modes have their own communities.

Keep in mind with the second way: twenty people on one server feel livelier than ten twice. The prices for a second server are on the product page.

What is kept when switching

Switching gamemodes is more harmless than many people fear. What stays:

• Your addons. They are in the addons folder or in the collection and are independent of the gamemode.
• Your server.cfg. Server name, password and download settings continue to apply.
• Your admin structure. Ranks and rights from ULX remain in place.

What is specific to a gamemode, on the other hand, stays where it is and waits: DarkRP jobs, TTT statistics, saved bases. If you switch back, everything is there again. That is why gamemodes can be tried out safely - an evening of Prop Hunt costs the DarkRP server nothing.

When the switch goes wrong

• The server starts in Sandbox. The gamemode was not found - usually a typo in the name or the addon is missing.
• The server does not start. The start map does not exist. The map name has to be exactly right.
• The gamemode runs, but with errors. Dependencies that the gamemode requires are missing.
• Players see error models. Map or model content is missing on the client - a case for FastDL.

In all four cases, the live console in the web interface names the cause at startup - a look there saves half the troubleshooting.

Frequently asked questions