How to fix error system-service-exception in Garry's Mod

Solution Steps

1. 1 Run Garry's Mod as Administrator. Navigate to the game folder, right-click the .exe → Properties → Compatibility → check 'Run this program as an administrator' → Apply. This gives Garry's Mod full system access and fixes permission-related crashes.
2. 2 Update Windows to the latest version. Settings → Windows Update → Check for updates. Install ALL updates, especially 'Optional' driver updates. Garry's Mod requires the latest Windows components for stability.
3. 3 Disable fullscreen optimizations. Right-click Garry's Mod.exe → Properties → Compatibility → check 'Disable fullscreen optimizations' → Apply. This prevents Windows from interfering with the game's rendering pipeline.
4. 4 Install Garry's Mod on an SSD if it's currently on an HDD. Slow disk reads during gameplay cause asset streaming stutters that can cascade into crashes. An SSD eliminates this bottleneck.
5. 5 Check your RAM stability. Press Windows key + R, type 'mdsched.exe' and press Enter → Restart now. Faulty RAM causes random crashes in Garry's Mod that are impossible to reproduce consistently.
6. 6 Temporarily disable your antivirus real-time protection and test Garry's Mod. Add the game folder to antivirus exclusions. Security software sometimes quarantines game files or blocks their execution.
7. 7 Lower Garry's Mod graphics settings temporarily. Set everything to Low/Off, disable Ray Tracing, disable DLSS/FSR. If crashes stop, increase settings one by one until you find the problematic setting — usually shadows, textures, or ray tracing.
8. 8 If Garry's Mod still crashes: uninstall the game, delete all remaining folders in SteamApps\common and %LOCALAPPDATA%, restart your PC, reinstall. This clean slate approach fixes stubborn corruption that verification misses.