Fix OpenGL Errors on Windows 10/11 Medium

Category: Troubleshooting

# OpenGL Troubleshooting

## Common Errors
- "GLW_StartOpenGL() - could not load OpenGL subsystem"
- Black screen on launch
- Menu flickering

## Solutions

### 1. Update GPU Drivers
- NVIDIA: GeForce Experience or nvidia.com/drivers
- AMD: AMD Software or amd.com/support
- Intel: Intel Driver & Support Assistant

### 2. Compatibility Mode
1. Right-click game .exe
2. Properties > Compatibility
3. Check "Run in compatibility mode for: Windows XP SP3"
4. Check "Run as administrator"

### 3. Force Software Renderer (last resort)
Add to launch options:
```
+set r_mode -1 +set r_customwidth 1920 +set r_customheight 1080
```

### 4. Disable Fullscreen Optimizations
Properties > Compatibility > "Disable fullscreen optimizations"

## Game-Specific
- **Q3A**: Disable "Lightmap" in video settings
- **UT99**: Use D3D9 renderer (utglr-d3d9)
- **CS 1.6**: Add `-gl` to launch options

Difficulty:
Medium

Category:
Troubleshooting

Last Updated:
Mar 8, 2026