Why does my Minecraft server keep crashing? Logs, OOM errors, and fixes

If a Minecraft server keeps crashing, first determine how the Java process ended. A plugin startup failure, Java exception, watchdog stop, Linux out-of-memory kill, and manual termination can all look like “offline” in a basic panel, but they need different fixes.

Preserve logs/latest.log, the matching file in crash-reports/, and the panel exit information before restarting repeatedly.

Start with four questions

1. Did the server finish startup before it failed?
2. Is there a crash report, or only an abruptly ended log?
3. What was the process exit status or signal?
4. What changed immediately before the first failure?

Copy the server before removing files or trying upgrades. Troubleshoot the copy where possible.

Failure during startup

Read from the first clear ERROR, not merely the last stack-trace line.

Common causes include:

• A plugin built for another Minecraft or Java version.
• A missing plugin dependency.
• Two versions of the same plugin in plugins/.
• Invalid YAML or another malformed configuration file.
• A server JAR that does not match the world's expected version.
• A port already used by another process.

Paper's plugin troubleshooting guide documents missing dependencies, invalid plugin descriptions, and ambiguous plugin names. Fix the named cause rather than deleting unrelated plugins.

Watchdog termination

The watchdog stops a server when one tick remains stuck beyond its configured limit. The report normally contains a server-thread stack trace showing what was executing.

Possible causes include a plugin doing blocking work, pathological entity behavior, synchronous chunk operations, storage stalls, or an overloaded main thread. Capture a spark profile before the next failure if the slowdown is reproducible and the server remains responsive long enough.

Java heap out of memory

An explicit java.lang.OutOfMemoryError: Java heap space means Java could not satisfy a heap allocation. It does not automatically mean the hosting plan is too small.

Check whether:

• -Xmx is lower than intended.
• A plugin retains memory continuously.
• The workload legitimately grew.
• Garbage collection frees meaningful memory.

Use spark memory inspection and compare heap after garbage collection over time. A leak may return after every restart, while an undersized but stable workload reaches a repeatable plateau. See the RAM calculator and sizing guide.

Linux killed the process

An abruptly ended Java log with exit signal 9 or host evidence of the OOM killer points outside Java's normal exception handling. The guest may have exhausted total physical memory even if Java stayed below -Xmx, because the operating system and native allocations also need room.

Check the system journal or ask the host for guest and host telemetry. Do not set -Xmx equal to every byte of the plan.

Disk full or filesystem errors

World saves, logs, backups, maps, and plugin databases consume storage. A full disk can prevent saves and corrupt partially written data. Check both free bytes and inodes. Move backups off the live volume rather than deleting the only recovery copy.

Recover safely

1. Preserve the failed state and logs.
2. Restore the last known-good backup into a separate directory.
3. Match its Java, server, and plugin versions.
4. Start privately and verify player and plugin data.
5. Apply one suspected fix.
6. Reproduce the triggering workload before returning traffic.

gummysnacks distinguishes a process that exited on its own as crashed and archives crash information for the panel. Live console, file access, metrics history, and backups provide the evidence needed for this sequence. Airbag is a planned, optional crash-protection feature with 2 GB and 4 GB emergency-RAM plans at different displayed hourly rates; it is not presented here as an available fix.

Sources and review

Reviewed July 15, 2026 against PaperMC's plugin troubleshooting documentation, Paper profiling guidance, and current gummysnacks crash-state, crash-archive, metrics, and supervisor sources.