How to fix 'Exception in server tick loop' in Minecraft
Exception in server tick loop means your Minecraft server crashed. Open the newest crash report, find the first "Caused by" line, and fix what it names.
TL;DR: "Exception in server tick loop" is the headline of a Minecraft
server crash, not the cause. Open the newest file in crash-reports, find
the first Caused by line, and fix the one mod, file, or setting it points to.
The Minecraft server runs everything in a loop, many times a second. When
something in that loop throws an error the server can't handle, it writes a
crash report and stops. The report's Description line says "Exception in
server tick loop", and the lines under it say what actually broke.
Find the cause in the crash report
Open the newest crash report
Paper's troubleshooting guide
says a crash report is saved in the server's crash report folder. That folder
is crash-reports, in the server's main folder. On
berrybyte, open Files in the dashboard
and open the newest file there.
Find the first 'Caused by' line
Skip past the funny comment at the top and the Description line.
Look for the first line that starts with Caused by, plus the few
lines right under it. That's the error behind the crash.
Note the mod, file, or error it names
Paper's guide says the top line of a stack trace shows where the
problem happened. Lines that start with at show the code that was
running. A package name like com.examplemod points to a mod, and a
file name points to a config file.
Fix that one thing, then start again
Make a backup first. Then change only
what the report points to and start the server. Keep Console open
until you see the Done line.
Here's a short example of what to look for. It's made up, but real reports follow the same shape:
---- Minecraft Crash Report ----
Description: Exception in server tick loop
java.lang.RuntimeException: Pump failed to tick
at com.examplemod.machines.PumpBlockEntity.tick(PumpBlockEntity.java:88)
at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1021)
Caused by: java.lang.IllegalStateException: Pump has no fluid tank
at com.examplemod.machines.FluidTank.get(FluidTank.java:42)In this example, com.examplemod is the mod to check, and the pump machine
is the block that crashed.
Use the crash notice on berrybyte
When a berrybyte server crashes, Overview shows a crash notice that tries to explain the crash in plain words. It can offer a fix button, such as turning off a mod, switching the Java version, or restoring a backup. Press What happened? to see the cause and the full log.
Past crashes are listed under Logs → Crashes for 7 days. Open one to read its log, or press Explain this crash if it hasn't been explained yet. Some explanations are written by AI from the log, so check them before you make big changes.
Common causes and how to check each one
The report tells you which of these it is. Check them in this order.
A mod that crashes or is missing something
Check whether the Caused by line or the at lines name a mod's package.
If they do, turn that mod off and start the server. On berrybyte, the
Mods list under Settings → Software & updates has a switch for each
mod, so you don't have to delete the file.
If the server starts without it, update the mod or leave it off. Still not sure which mod it is? Paper's guide suggests splitting your plugins into two groups and testing one group at a time, and the same works for mods.
Mods built for another loader or Minecraft version
Check that every mod matches the server's loader and Minecraft version. A Fabric mod won't run on Forge, and a mod for one release may not load on the next. How to add mods to a Minecraft server covers loaders, and How to update a Minecraft server covers version changes.
Something broken in one spot of the world
Check whether the crash names a block, mob, or item, often with a position in the world. If the same thing crashes the server each time it starts, the problem may be saved in the world itself. Restoring a backup from before the first crash is the safest fix.
Running out of memory
Check for java.lang.OutOfMemoryError in the report or in logs/latest.log.
That means the server needs more RAM, or fewer heavy mods.
On berrybyte, 8 GB suits light modding and 12 GB suits a busier modded world. The RAM calculator and How much RAM for a Minecraft server help you size it. If the RAM is enough but the server still struggles, see Aikar's flags.
The wrong Java version
Check that the server runs the Java version its Minecraft version needs. Mojang's version data lists these:
| Minecraft version | Java version |
|---|---|
| 26.1 and newer | Java 25 |
| 1.20.5 to 1.21.11 | Java 21 |
| 1.18 to 1.20.4 | Java 17 |
| 1.17 and 1.17.1 | Java 16 |
| 1.16.5 and older | Java 8 |
On berrybyte, pick it under Settings → Startup → Java version. If the crash notice offers Switch to Java and a number, that button does the same thing.
A broken config or JSON file
Check whether the report names a file, such as a .json or .toml file,
or an error with "JSON" or "syntax" in it. Open that file in Files and
look for a missing bracket or comma. Make a backup before you edit or remove a
file like whitelist.json, so you can put it back.
If it happens in single player
The same error can show up in single player too. The Minecraft Wiki's
crash article names the
.minecraft/crash-reports folder, and you read the report the same way.
Look for the first Caused by line, then check the mod it names.
Stop it from happening again
These crashes often start right after a change, like a new or updated mod. Make a backup before you add or update mods, and change one mod at a time so you know which one broke. If you run a modpack, update the whole pack through Install a Minecraft modpack instead of swapping single mods.
Server starts but players can't get in? That's a different problem, so see Can't connect to a Minecraft server.
Crash help on berrybyte
Every berrybyte Minecraft plan has automatic backups, manual snapshots, and a crash notice that tries to explain what went wrong. Plans start at $9.95 a month on the Minecraft hosting page. If a crash keeps coming back, open a support ticket.
Frequently asked questions
What does 'Exception in server tick loop' mean?
It means the Minecraft server's main loop hit an error it couldn't recover from, so the server stopped. The message is only the headline. The real cause is in the "Caused by" lines and the stack trace further down the same crash report.
Is 'Exception in server tick loop' caused by mods?
On a modded server, a mod is often the first thing to check, because the stack trace usually names its package. It isn't always a mod, though. Running out of memory, the wrong Java version, or a broken config file can stop the server too, so read the report before you remove anything.
Can 'Exception in server tick loop' delete my world?
The error stops the server. If the world won't load after the crash, restore a backup from before it started. On berrybyte, every plan has automatic backups, and you can restore one from Backups in the dashboard.
How do I fix 'Exception in server tick loop' without losing my world?
Make a backup first, then change one thing at a time. Turn off or update the mod the crash report names instead of deleting files, and start the server again after each change. If nothing works, restore the backup you made.
Where is the crash report for a Minecraft server?
A server saves crash reports in the crash-reports folder inside its main folder, and the full log is logs/latest.log. On a berrybyte server, open Files in the dashboard to find both. Recent crashes are also listed under Logs → Crashes.