How to Install Garry's Mod and Join a Server

Almost everyone's first hour in Garry's Mod is spent looking at pink and black checkerboards and red ERROR signs where the props should be.

That is not a broken install. It is the single defining quirk of this game, it has a specific cause, and it is worth understanding before you buy anything — because the fix sometimes means buying a second game.

Garry's Mod is a sandbox built on Valve's Source engine. It ships with tools and almost no content of its own. Everything you see in it is borrowed from other Source games, and if you do not own the game a map was built from, the engine has nothing to draw. There are 351 servers listed here, and the busiest ones are all running gamemodes that assume you have the missing content.

What you need

• A Steam account
• Garry's Mod, which is a paid game
• Around 5 GB, before addons
• Ideally, Counter-Strike: Source — see below

Our Steam guide covers the account, and getting two-factor on it before you own anything is time well spent.

The Counter-Strike: Source question

This is the part that catches everyone.

An enormous share of Garry's Mod maps and addons — DarkRP cities, TTT maps, prop hunt levels — were built using textures and props from Counter-Strike: Source. Those files are not in Garry's Mod. If you do not own CS:S, the engine substitutes the missing texture with a checkerboard and the missing model with an ERROR sign.

You do not have to buy it. Plenty of servers run maps that need nothing extra, and some server owners package the required content themselves. But if you intend to play DarkRP or TTT seriously, owning CS:S removes about ninety per cent of the problem permanently, and it is usually a few pounds.

Half-Life 2 and its episodes cover most of the rest.

Step 1: install, then mount

Buy Garry's Mod on Steam and install it. The files land in steamapps/common/GarrysMod.

If you own CS:S, install that too, then launch it once and quit. Garry's Mod cannot mount content from a game that has never been run and unpacked.

Then start Garry's Mod, and from the main menu open the Games panel — the controller icon on the bottom right. Every Source game you own that it can borrow from is listed there. Make sure CS:S is ticked.

Restart Garry's Mod after mounting. It does not always pick it up live.

Step 2: turn on the console

Options, then Advanced, and tick Enable Developer Console. Or add -console to the launch options through the game's Properties in Steam.

You need it to join servers by address, and every troubleshooting instruction you will ever read for this game starts with "open the console".

Step 3: understand what you are joining

Garry's Mod is not one game. The server you pick determines what you are actually playing, and the differences are total.

Sandbox is the game as sold: physics, a toolgun, props, no objective. It is the best place to start and the worst place to judge the game from, because nothing happens unless you make it happen.

Trouble in Terrorist Town is a social deduction game. Most players are innocent, a few are traitors, everyone can shoot everyone, and the round is spent working out who is lying. It is the reason a lot of people own this game.

DarkRP is a roleplay economy — jobs, money, printers, police, and a very large number of unwritten rules that regulars will enforce loudly. Read a server's rules page before joining one, genuinely.

Prop Hunt is hide and seek where the hiders are props. It explains itself in thirty seconds.

Murder, Deathrun, Cinema and a long tail of others each have their own populations. Our Garry's Mod gamemode guide goes through which is which.

The server list shows what each machine is currently running, so you can pick the mode first and the server second.

Learn the controls in singleplayer first

Start a single-player sandbox game before joining anything. Two keys do most of the work and neither is obvious:

• Q opens the spawn menu — props, weapons, NPCs, tools.
• C opens the context menu, which is how you recolour things, change material, and adjust whatever tool you are holding.

The physgun is the blue one. Hold left mouse to pick a prop up, scroll to push it away or pull it closer, right-click to freeze it in place. Freezing is what separates building something from watching it fall over.

The toolgun is the other one, and the tool it uses is whatever you selected in the Q menu. Weld, rope, thruster, balloon and the rest all live there.

Twenty minutes of this offline will save you from being the person on a sandbox server who cannot work out why their car keeps collapsing.

Step 4: connect

The in-game browser is under Find Multiplayer Games. It works and it is slow.

To join directly, open the console and type:

connect 51.79.148.62:27015

The port matters. 27015 is the default; a host running twenty Garry's Mod servers on one machine has nineteen of them somewhere else.

The first join is genuinely slow

This is the other thing to be ready for. A DarkRP or TTT server may push several hundred megabytes of addons before letting you in — custom weapons, jobs, maps, models, sounds.

On a server with a properly configured fast download host this takes a minute or two. On one without, it can take considerably longer, and the loading screen will sit on a filename that appears to be doing nothing.

It is doing something. Leave it. This happens once per server, not once per join, and the files are cached afterwards.

Step 5: addons, and how to avoid ruining your install

Garry's Mod uses the Steam Workshop. Subscribing to an addon downloads it and loads it every time you start the game.

Two pieces of advice that will save you an evening:

Do not subscribe to hundreds of things. Every subscribed addon is loaded at startup, and a bloated subscription list is the most common cause of five-minute load times and crashes on join. If the game has become slow, this is why.

Server content is separate. You do not need to subscribe to anything to play on a server. The server sends what it needs. Subscribing to a collection "for" a server is almost never required and frequently makes things worse.

If your game has become unusable, unsubscribe from everything and add things back deliberately. There is no gentler fix.

The chat commands most servers understand

Garry's Mod servers run their own administration addons rather than one standard platform, so this varies more than it does on other Source games. Even so, a few commands are close to universal on populated servers.

Typed into normal chat:

• !motd — the server's rules page. On a DarkRP server, read it before doing anything. The rules are enforced and "I did not know" is not a defence anyone accepts.
• !menu — opens whatever administration or shop menu the server uses.
• !report or @ followed by your message — contacts staff. On many DarkRP servers @ alone opens an admin chat.
• !rtv — a map vote, where the gamemode uses one. TTT servers usually do; DarkRP servers usually do not, because the map is the point.

If a command does nothing, the server does not have it. There is no penalty for trying.

Problems you will actually hit

ERROR signs everywhere. Missing models. Usually CS:S is not owned, not installed, not mounted, or was never launched once after installing.

Pink and black checkerboards. Missing textures, same cause.

Stuck on "Client info sent" or a filename. Still downloading. Wait it out on the first join.

The game takes minutes to start. Too many Workshop subscriptions.

Kicked immediately after joining. Some DarkRP servers enforce a minimum Steam account age or playtime to keep bot accounts out. Nothing on your end fixes this except playing elsewhere for a while.

"Missing map". The server is running a map it did not send you, usually because its download host is misconfigured. That one is the server owner's problem.

Settings that survive

Create garrysmod/cfg/autoexec.cfg and put anything you want to keep there. config.cfg is rewritten on exit and will discard your edits.

Hosting a game for friends

Garry's Mod will let you host from inside the game — Start New Game, pick a map and a gamemode, and set the player count above one. That creates a listen server: your machine is both playing and hosting.

It works, and it has two limits worth knowing before you promise anyone anything.

Your friends cannot reach it from the internet unless the port is open on your router. That is a separate job, and our port forwarding guide walks through it properly, including why the advice to put your machine in the DMZ is bad advice.

And the server dies when you close the game. For anything you want to exist when you are asleep, you need a machine that stays on — which is where a dedicated server or rented hosting comes in, and where the server monitoring guide becomes relevant.

For an evening with four friends, a listen server is genuinely fine.

Where to go next

Garry's Mod is the easiest way into Source engine community servers, but it is not the only one. Counter-Strike: Source — which you may now own anyway — Team Fortress 2, Half-Life 2: Deathmatch and Day of Defeat: Source all run on the same engine, use the same console commands, and have the same server culture.

Everything you learned here about connect, fast downloads and autoexec.cfg works identically on all of them.

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JoinGG is a live directory of community game servers. Every listing is queried directly every fifteen minutes, so the player count you see was measured rather than reported by its owner, and each one carries a copyable connect address. Garry's Mod servers are listed here, and every game on the site has its own hub. Player counts across every game are on the statistics page, and Garry's Mod's own numbers — servers online, players now, activity by hour — are on its statistics page.