If Garry's Mod won't open, first check Steam isn't still holding an old copy of the game open. Then verify your game files. Those two steps fix most launch problems.
Find your symptom below. Each section goes from the quickest fix to the slowest.
Steam Says Garry's Mod Is Already Running
You press Play, nothing opens, and Steam shows Stop instead of Play. An old copy of the game never closed properly and is stuck in the background.
Open Task Manager
Press Ctrl + Shift + Esc. If it opens small, click More details.
End the Game
Go to the Details tab. Find gmod.exe or hl2.exe (the name depends on your version). Select it and click End task.
Restart Steam
Click Steam in the top left and choose Exit. Open Steam again and press Play.
If the process won't end or comes straight back, restart your PC.
Failed to Start Game (Missing Executable)
Steam shows Failed to Start Game (Missing Executable) when a game file is missing or another program is blocking it. Valve says antivirus software is the most common cause.
Check Your Antivirus
Open your antivirus and look at its quarantine list. If it caught a Garry's Mod file, restore it and mark it as safe. Then add your Garry's Mod folder to its exclusions.
Restart and Verify
Restart your PC. In Steam, right-click Garry's Mod, choose Properties, go to Installed Files and click Verify integrity of game files.
If it still fails, Valve asks you to contact Steam Support with a full screenshot of the error.
Disk Write Error
A disk write error means Steam couldn't save files while installing or updating the game. Try these in order:
Check Free Space
Make sure the drive Garry's Mod is on has free space. Delete or move something if it's nearly full.
Restart Your PC
A restart releases files that another program has left open.
Clear the Download Cache
In Steam, click Steam, then Settings, then Downloads. Click Clear Cache next to Clear Download Cache. Steam signs you out, so sign back in and start the update again.
Repair the Library Folder
In Settings, go to Storage. Pick the drive Garry's Mod is on, open the ... menu and choose Repair Folder.
Check the Drive for Errors
In File Explorer, right-click the drive and choose Properties. Go to Tools and click Check under Error checking.
If the error keeps returning on the same drive, move Garry's Mod to another drive. In Settings, Storage, add a folder on the other drive, then select Garry's Mod and click Move.
Content File Locked
Content File Locked means Steam needs to replace a file but something has it open. Antivirus scanning and a copy of the game left running are common causes.
- End any
gmod.exeorhl2.exein Task Manager, as in the first section. - Add your Steam library folder to your antivirus exclusions.
- Restart your PC, then clear the download cache and repair the library folder as above.
Facepunch treats this as a Steam problem, not a Garry's Mod one. If none of the above works, contact Steam Support.
Black Screen or Closes on Startup
The game opens to a black screen, or closes before the main menu.
Facepunch lists the Discord overlay, RivaTuner Statistics Server (part of MSI Afterburner) and IOBit Malware Fighter as known problems. Turn off or exit anything with an in-game overlay, then try again.
A crash on startup with no error is very often the driver. Update it from your graphics card maker's website. If a new driver caused it, roll back to an older one.
Add -noaddons -noworkshop to your launch options. If the game starts, an addon is the problem. The crashing guide shows how to find which one.
Add -autoconfig to your launch options and start the game once. It picks settings for your PC. Remove -autoconfig once the game opens.
A broken resolution setting can leave you on a black screen. Add -sw to start in a window, or set a size such as -w 1280 -h 720. Remove them once the game opens and set your resolution in Options.
Failed to Create D3D Device
This error usually appears on laptops with two graphics chips. Garry's Mod starts on the weaker built-in chip instead of your graphics card.
Open Graphics Settings
In Windows Settings, go to System, Display, then Graphics.
Pick the Game
Add Garry's Mod's .exe from your game folder. To find the folder, right-click Garry's Mod in Steam and choose Manage, then Browse local files.
Choose High Performance
Set it to High performance and start the game again.
Forcing a resolution with -w and -h can also clear this error.
How to Set Launch Options
Right-click Garry's Mod in Steam and choose Properties. On the General tab, type into Launch Options. Put a space between options. There's no save button. Close the window and Steam keeps what you typed.
| Launch option | What it does |
|---|---|
-noaddons | Turns off addons in your garrysmod/addons folder |
-noworkshop | Turns off your Workshop addons |
-autoconfig | Resets video settings to suit your PC |
-sw | Starts the game in a window |
-w 1280 -h 720 | Starts at that resolution |
-condebug | Saves the console to garrysmod/console.log |
Remove test options once the game works. For options that improve FPS, see the performance guide. To run the 64-bit version, use the Betas tab as the 64-bit guide shows, not a launch option.
Last Resort: Reinstall
If nothing above works, uninstall Garry's Mod from Steam with Manage, then Uninstall, and install it again. Back up garrysmod/data, garrysmod/saves and anything you put in garrysmod/addons yourself first. Workshop addons download again on their own.
If the game opens but Steam errors stop you playing, see Fix Steamworks API and No SteamUser Errors.
Want a server to try it on? Justified is a Garry's Mod DarkRP server: justified.gg.
