Fix "Can't keep up! Is the server overloaded? Running 2000ms or 40 ticks behind"
What the Minecraft console warning Can't keep up! Is the server overloaded? means, when to ignore it, and how to find and fix the real cause with spark.
The warning in your server console:
[Server thread/WARN]: Can't keep up! Is the server overloaded? Running 2048ms or 40 ticks behindWhat it means #
A Minecraft server runs 20 ticks per second, so each tick has 50 ms. When ticks take longer, the server falls behind. When it's more than about 2 seconds behind, it gives up catching up, skips ahead and prints this warning. 2048ms or 40 ticks means about two seconds of game time were skipped: players see rubber-banding, slow mobs and delayed blocks.
1. Does it matter? #
- Once, right after start, a restart, a backup or loading a new world: normal. The server was busy loading. Ignore it.
- Every few minutes while people play: something is using too much tick time. Keep going.
- Huge numbers (like
60000ms) once: the server or the machine paused, for example during a long save. If it repeats, treat it like the case above.
If players lag but this warning never appears, the server is keeping up and the lag is probably their connection. See fix Minecraft lag, step 1.
2. Measure with spark #
spark is a profiler plugin (Paper and Purpur include it). In the console:
spark tps
spark profiler start --timeout 60spark tps shows TPS (20 is perfect) and MSPT (milliseconds per tick; under 50 is fine). After 60 seconds the profiler gives you a link. Open it and expand the biggest branch under the server thread: it names the plugin, entity type or task that eats the time.
3. Fix the top cause #
| spark shows mostly… | Do this |
|---|---|
| Chunk generation / world gen | Players exploring new land. Pre-generate with the Chunky plugin: chunky radius 3000, chunky start, and set a world border. |
| Entities (mobs, items, villagers) | Big mob farms, item piles or hundreds of villagers. Lower farm sizes, clear dropped items, and use Paper's entity limits. |
| Redstone / hoppers / block updates | Fast clocks and long hopper chains. Turn off unused machines; hopper chains can be replaced with water streams. |
| A plugin's name | Update it to a version for your server version, check its config, or remove it. |
| Many chunks loaded | Lower simulation-distance (and view-distance) in server.properties, for example simulation-distance=6. |
On a vanilla server, switching to Paper or Purpur alone often fixes it, since they run the same game much faster.
4. Memory and garbage collection #
If the spark report shows long GC (garbage collection) pauses, Java is struggling with memory: the server is near its RAM limit, or a plugin or huge world is holding too much. Reduce what fills memory (loaded chunks, entities, big plugin caches) or move to a plan with more RAM. See how much RAM a Minecraft server needs. More RAM doesn't fix a slow plugin or a lag machine; measure first.
Want a clean state every day? Add a daily restart in Schedules.
FAQ #
Can I just hide the warning?
You can, but the lag stays. The message is a symptom; players feel the skipped ticks either way.
Is 'Can't keep up' caused by the player's internet?
No. It's printed by the server about its own tick speed. Player internet problems show as high ping, not this warning.
I only see it when someone flies with an elytra.
That's chunk generation in new land. Pre-generate the world with Chunky and set a world border.
Still stuck? Use the live chat on the panel or ask in the ESN Systems Discord. Last updated November 3, 2026.