Troubleshooting
Having issues? This guide covers common problems and their solutions.
Game Won’t Launch
Section titled “Game Won’t Launch”Java Issues
Section titled “Java Issues”Symptoms: Game fails to start, Java errors
- Ensure Java 21 is installed 2. In Prism Launcher: Settings → Java → Auto-detect 3. Or manually select your Java 21 installation 4. Try launching again
Get Java 21: Adoptium Temurin
Not Enough Memory
Section titled “Not Enough Memory”Symptoms: Crash on launch, “Out of Memory” error
- Edit instance → Settings → Java 2. Increase Maximum memory allocation 3. Recommended: 4-6 GB 4. Don’t exceed 50% of your total RAM
Missing Libraries
Section titled “Missing Libraries”Symptoms: Error about missing files
- Right-click instance → Edit → Mods 2. Look for mods with warning icons 3. Try: Delete mods → Re-add from Modrinth/CurseForge 4. Or reinstall the entire modpack
Performance Issues
Section titled “Performance Issues”Low FPS
Section titled “Low FPS”Quick fixes:
- Lower render distance (8-12 chunks)
- Disable shaders
- Allocate more RAM (up to 6-8 GB)
- Close other applications
Stuttering / Lag Spikes
Section titled “Stuttering / Lag Spikes”Causes and solutions:
| Cause | Solution |
|---|---|
| Garbage collection | Use recommended JVM arguments |
| Chunk loading | Lower simulation distance |
| Shader compilation | Wait for initial compile |
| World generation | Wait for chunks to generate |
Long Loading Times
Section titled “Long Loading Times”- First launch is always slower (caching)
- Allocate RAM on SSD, not HDD
- Reduce mods if heavily modded
- Be patient with shader compilation
Shader Problems
Section titled “Shader Problems”Shaders Won’t Enable
Section titled “Shaders Won’t Enable”- Update GPU drivers 2. Check GPU supports OpenGL 4.6 3. Try a different shader pack 4. Disable Voxy temporarily
Black Screen with Shaders
Section titled “Black Screen with Shaders”- Wait 1-2 minutes (compilation) 2. Press F3+R to reload shaders 3. Try pressing Escape 4. Force-quit and disable shaders via config
To disable shaders without launching:
- Open
.minecraft/config/iris.properties - Set
enableShaders=false - Launch game
- Re-enable after fixing issue
Visual Glitches
Section titled “Visual Glitches”- Update GPU drivers (most common fix)
- Try different shader preset
- Check for shader pack updates
- Report to shader pack developer
Mod-Specific Issues
Section titled “Mod-Specific Issues”LODs not generating:
- They generate as you explore
- Try
/voxy import worldcommand - Ensure enough RAM allocated
LOD gaps or holes:
- Normal during generation
- Revisit area to regenerate
- Check Voxy settings
Voice Chat Not Working
Section titled “Voice Chat Not Working”On supported servers:
- Check microphone is connected
- Verify mic is selected in mod settings
- Test with V key (push-to-talk)
- Check system volume mixer
Xaero’s Maps
Section titled “Xaero’s Maps”Waypoints not showing:
- Press U to toggle waypoints
- Check waypoint visibility settings
- Ensure you’re in the right dimension
Map not updating:
- Cave mode may be enabled
- Check map settings
- Try Shift+M to refresh
Server Connection Issues
Section titled “Server Connection Issues”Can’t Connect to Server
Section titled “Can’t Connect to Server”| Issue | Solution |
|---|---|
| Version mismatch | Ensure server is 1.21.x |
| Mods required | Server may need specific mods |
| Chat signatures | Check No Chat Reports settings |
| Firewall | Allow Java through firewall |
Kicked for “Invalid Signature”
Section titled “Kicked for “Invalid Signature””This relates to chat signing:
- Open Mods → No Chat Reports
- Try different compatibility modes
- Contact server admin
Crashes
Section titled “Crashes”Finding Crash Logs
Section titled “Finding Crash Logs”Location:
.minecraft/crash-reports/- Crash reports.minecraft/logs/latest.log- Latest log
Sharing logs: Use mclo.gs to paste and share
Reading Crash Reports
Section titled “Reading Crash Reports”Look for:
- The mod name in the stack trace
- “Caused by:” sections
- Memory errors (out of memory)
- Missing class errors
Common Crash Causes
Section titled “Common Crash Causes”| Error | Cause | Solution |
|---|---|---|
| OutOfMemoryError | Not enough RAM | Allocate more |
| NoClassDefFoundError | Missing dependency | Install required library |
| MixinApplyError | Mod conflict | Remove conflicting mod |
| OpenGL Error | GPU/driver issue | Update drivers |
Resetting Configuration
Section titled “Resetting Configuration”Reset Specific Mod Config
Section titled “Reset Specific Mod Config”- Close Minecraft 2. Open
.minecraft/config/3. Delete the folder/file for that mod 4. Launch game (defaults will regenerate)
Full Config Reset
Section titled “Full Config Reset”- Back up your
savesfolder 2. Back upscreenshotsif desired 3. Delete the entire instance 4. Re-import the modpack 5. Restoresavesfolder
Getting Help
Section titled “Getting Help”If you can’t solve the issue:
- Check existing issues: GitHub Issues
- Create a bug report: Include:
- Modpack version
- What you were doing
- Crash log (use mclo.gs)
- Steps to reproduce
- Check mod-specific support for individual mod issues