Before You Begin: The Fundamentals
Verify your ROM: Corrupted ROMs are a common cause of issues. Check file integrity with checksums if possible. Re-dump if you have the means.
Check compatibility lists: Most emulators have compatibility databases. Check if your specific game is known to work, has issues, or needs specific settings.
Update your emulator: Bugs get fixed. Performance improves. Before troubleshooting extensively, make sure you're on the latest stable or nightly build.
One change at a time: When troubleshooting, change one setting at a time. If you change five things and it works, you don't know which fixed it.
Document your working settings: When you find settings that work, screenshot or write them down. You'll need them again.
Game Won't Launch or Black Screen
BIOS issues (PS1/PS2/Dreamcast): Most disc-based consoles need BIOS files. Without correct BIOS, you get black screens. Verify BIOS files are present and correctly named.
Graphics backend: Try switching between Vulkan, OpenGL, and Direct3D. Some games work only on specific renderers. Vulkan is generally best on modern hardware.
Resolution too high: If you set internal resolution too high (4x, 8x), some games black screen. Start at native or 1x, then increase.
Fast memory/speed hacks: Aggressive speed settings can cause black screens. Disable speed hacks and test.
Cheat codes active: Disable all cheats. Some codes cause games to fail to boot or black screen immediately.
Region mismatch: Some emulators are picky about region matching. PAL game with NTSC BIOS, or vice versa, can cause issues.
Choppy Audio and Audio Issues
Audio usually means performance: Choppy, stuttering audio is almost always a sign the emulator isn't running full speed. Check your FPS counter.
Buffer settings: Increase audio buffer size. Larger buffers prevent underruns but increase latency. Find the sweet spot for your device.
Time-stretch audio: Some emulators can stretch audio to match emulation speed. Prevents choppiness but causes pitch shifts. Better than stuttering.
Different audio backends: Try OpenSL, AAudio, or XAudio2 depending on platform. Some work better on specific devices.
Bluetooth audio latency: Bluetooth adds latency. Not an emulator issue, but can make audio seem 'off.' Use wired headphones for testing.
Mute and test: Try muting audio and checking if performance improves. If yes, it's definitely an audio backend issue.
Performance and Speed Issues
Check actual emulation speed: Enable FPS counter. 100% speed = full speed. 60fps for NTSC, 50fps for PAL. If you're at 85%, that's your problem.
Lower resolution: Start at native or 1x internal resolution. Get the game running full speed first, then increase resolution.
Enable speed hacks: MTVU for PS2, various options for other emulators. These exist specifically for performance on weaker hardware.
Close other apps: On both Android and Windows, background apps steal CPU time. Close everything except the emulator.
Thermal throttling: If device gets hot, performance drops. Check temperatures. Ensure vents aren't blocked. Consider active cooling.
Check power mode: Device might be in power-saving mode. Set to Performance/Balanced in system settings for consistent clocks.
Controller and Input Problems
Verify controller is detected: Check emulator input settings. Does it see your controller? If not, restart emulator or device.
Re-map from scratch: Delete current mapping and re-map all buttons. Sometimes mappings get corrupted or confused.
Analog vs Digital: Some older games only accept digital input. Enable 'Analog to Digital' in RetroArch or similar settings if sticks aren't working in old games.
Dead zones: If character drifts or buttons seem 'sticky,' adjust dead zones. 8-15% is typical. Higher if you have stick drift.
Steam Input conflicts: On Windows handhelds using Steam, Steam Input can conflict with native controller support. Try disabling Steam Input for the game.
Test in controller settings: Most emulators have a controller test screen. Verify each button registers before launching games.
Save States and Save Data Issues
Save state incompatibility: Not all games work well with save states. Some crash when loading states. Use in-game saves when possible.
Save state timing: Create save states in menu screens or safe areas, not during loading screens or intense action. More stable.
Version mismatch: Save states often don't work between emulator versions. Keep old emulator version if you have important states.
In-game save corruption: Rare but happens. Backup your save files regularly. Use cloud sync if available.
Memory card emulation: Some emulators need memory card files created. Check emulator docs for PS1/PS2 memory card setup.
Permission issues: On Android, ensure emulator has storage permissions. On Windows, don't run emulator as admin unnecessarily.
Graphics Glitches and Visual Issues
Resolution scaling artifacts: Upscaling (2x, 4x native) can cause graphical glitches. Try native resolution to verify issue is upscaling-related.
Texture filtering: Try different filtering options. Some games glitch with forced bilinear or anisotropic filtering.
Hardware vs Software renderer: Software renderer is more accurate but slower. If hardware has glitches, test software renderer to confirm.
Skip BIOS intro: Some games have issues if you skip the BIOS boot screen. Let the full boot sequence play.
Widescreen patches: Community patches can cause graphical issues. Disable to verify. Some UI elements stretch or glitch.
Cheat codes: Disable all cheats. Cheats can cause visual glitches, missing textures, or other issues.
Platform-Specific Issues
Android file permissions: Android 11+ scoped storage causes issues. Ensure emulator has 'All files access' permission in system settings.
Android scoped storage workarounds: Some emulators struggle with scoped storage. Use /Android/data/[emulator]/ or Documents folder for ROMs.
Windows HDR conflicts: If Windows HDR is enabled, some emulators display wrong colors. Disable HDR for emulation or use borderless windowed.
Windows GPU selection: Windows may run emulator on integrated GPU instead of dedicated. Force per-app GPU in Windows Graphics Settings.
Steam Deck controller order: Some games get confused by multiple virtual controllers. Check controller order in Steam Input settings.
Steam Deck game mode vs desktop: Some emulators behave differently. If issues in one mode, test the other.