Minecraft server won't start? How to find the cause and fix it
A server that stops right after you start it almost always says why in its console or in logs/latest.log. Find your message in the table below, then jump to the fix.
Start with the log
Watch the console as the server starts, or open logs/latest.log afterwards. Read the first error, not the last line: later lines are usually a result of it. The server is up when the log says “Done”.
What your error means
| Message | Cause and fix |
|---|---|
| You need to agree to the EULA | eula.txt still says false. Set it to true. |
| Unable to access jarfile | The jar file name or folder is wrong. Check the start command. |
| Invalid or corrupt jarfile | The download is incomplete. Download the jar again. |
| UnsupportedClassVersionError | Java is too old for this server. See which Java version a Minecraft server needs. |
| Could not reserve enough space for object heap | You asked Java for more memory than the machine has. See the guide to Minecraft memory errors. |
| FAILED TO BIND TO PORT | The port is already in use, or server-ip is wrong. See the guide to this error. |
| Could not load plugin | The plugin is broken or built for another Minecraft version. Update or remove it. |
| Failed to load level | The world is damaged. Restore a backup. |
Agree to the EULA
The first time you run the server, it creates eula.txt and stops. Open the file and change the last line to true, which means you agree to the Minecraft EULA at aka.ms/MinecraftEULA:
eula=true
Then start the server again.
Check the start command and the jar
A typical start command looks like this:
java -Xms2G -Xmx2G -jar server.jar --nogui
Run it from the folder that contains the jar, and make sure the file name in the command matches the real file name. List the folder with ls on Linux or dir on Windows to see it. If the jar is damaged, download it again from the software's official site.
Rule out plugins and mods
If the log names a plugin, update it to a version that matches your Minecraft version, or remove it. If the cause is not clear, move everything out of the plugins folder and start the server. When it starts, put the plugins back in small groups to find the one that breaks it. Plugins, Fabric mods and Forge mods are not interchangeable, so use only what your server software supports.
Damaged worlds
Errors about region files or level.dat mean part of the world is corrupted, often after a crash or a full disk. Stop the server, copy the world folder somewhere safe and restore the latest backup. Do not delete a world before you have copied it.
Still won't start?
Send the last 100 lines of the log together with your Minecraft version, your server software and build, and the output of java -version. With those, someone can usually name the cause in one reply.
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