The problem
What exit code -1 means in Minecraft and how to fix it, from mod crashes during loading to driver and memory settings.
Possible causes
- The game stopped unexpectedly during loading, often because of a mod error.
- Custom JVM arguments in the launcher that the Java version does not accept.
- Too much memory allocated for the amount of RAM in the PC, or too little for the modpack.
- Outdated graphics drivers, especially after a Windows update.
How to identify the cause
- Open
logs/latest.login the instance folder and scroll to the end. The last lines before the log stops show what the game was doing. - If there is a file in
crash-reports, it names the failing mod in the Description and stack trace. - If the log ends without any error, suspect drivers or memory settings rather than a mod.
Step-by-step fix
- Remove any custom JVM arguments you added and launch with the launcher's defaults.
- Set the memory allocation to a sensible value. The RAM calculator gives a starting point.
- Update your graphics drivers.
- Check the crash report for a mod name and update or remove that mod.
- Launch once with no mods to confirm the base game and loader work.
If that did not work
- Reinstall the loader version for the instance; a partial download can leave missing libraries.
- Try another launcher (Prism Launcher, the official launcher or your modpack's launcher) to rule out a launcher-specific problem.
Affected versions
All Minecraft versions, Java Edition.
Frequently asked questions
Is exit code -1 different from exit code 1?
Both mean the game stopped abnormally. The number alone does not tell you the cause; the log does.