How to read Minecraft server logs and find the first error

All log files are in the server folder, which you open in the Files tab. These are the ones that matter:

Minecraft starts a new latest.log at every start of the server, and when the date changes while it runs. The previous file is packed into a .log.gz file with its date in the name, so every run and every day has a file of its own.

The Console tab shows the log while the server writes it and keeps the last 2,000 lines in view. The bar above the log has these controls:

The Errors filter keeps only lines with ERROR in them. The at lines of a stack trace under an error carry no level, so the filter hides them. Use the filter to find the error and its time, then switch back to All levels and scroll to that time to read the whole block.

When the server is offline, the console can stay empty or show only part of the last run. The complete log of that run is in logs/latest.log.

1. Open the Files tab and click the logs/ folder.
2. Click Edit next to latest.log to read it in the panel. Close it with Cancel; a log needs no saving.
3. For an older day, click Download next to its .log.gz file and unpack it on your computer. 7-Zip does this on Windows, and a double click does it on a Mac.
4. Crash reports are in the crash-reports folder in the top folder. Open them with Edit as well.

The editor shows up to about 2 MB of a file. A bigger log opens with the note Shown truncated, saving would cut the file, download it instead. and shows only the start, without the newest lines at the end. Download such a file and open it on your computer.

To find what a player said, the Chat history card under the console searches these files up to 14 days back; see search the chat history of your Minecraft server.

[17:42:08] [Server thread/INFO]: Steve joined the game

The Console tab shows each line as time, level and message, without the thread. Fabric, Forge and NeoForge also write the name of the mod or class behind each line, and Forge and NeoForge put the date before the time.

One problem often sets off a chain of errors. The first one in the chain is the cause, and the ones after it follow from it. To find it:

1. Note when the problem happened: the time of the crash, the lag or the player report.
2. Open the log of that moment: latest.log for the current run, or the .log.gz file of that day.
3. Go to that time and read upward to the first WARN or ERROR line before it.
4. Read that line and the lines under it. A plugin or mod named there is the first suspect.
5. For a server that fails at startup, read latest.log from the top down instead. The first error you meet is the one that counts.

Repeated lines are a clue too. The same warning hundreds of times a minute points at one plugin, farm or entity that keeps failing.

A log that ends without Stopping server and Saving worlds means the server did not stop normally. Read the last lines before the end; they show what it was doing when it stopped.

Under many errors is a block of lines that start with at. That block is a stack trace: the path through the code at the moment something failed. An example from a Paper server:

[17:42:08] [Server thread/ERROR]: Could not pass event PlayerInteractEvent to ExamplePlugin v2.1.0
java.lang.IllegalStateException: Could not open the shop menu
	at com.example.plugin.ShopMenu.open(ShopMenu.java:112) ~[ExamplePlugin-2.1.0.jar:?]
	at com.example.plugin.ClickListener.onClick(ClickListener.java:48) ~[ExamplePlugin-2.1.0.jar:?]
	at io.papermc.paper.plugin.manager.PaperEventManager.callEvent(PaperEventManager.java:54) ~[paper-26.2.jar:?]
Caused by: java.lang.NullPointerException: Cannot invoke "String.length()" because "name" is null
	at com.example.plugin.ShopConfig.getItemName(ShopConfig.java:31) ~[ExamplePlugin-2.1.0.jar:?]
	at com.example.plugin.ShopMenu.open(ShopMenu.java:108) ~[ExamplePlugin-2.1.0.jar:?]
	... 2 more

• The first line says what the server was doing: passing a player's click to ExamplePlugin.
• The exception line names the kind of error and gives a short message.
• The `at` lines read from the top down, and the top one is where it failed. The first at line that does not start with net.minecraft, org.bukkit, io.papermc or java. belongs to the plugin or mod at fault. On modded servers, net.fabricmc, net.minecraftforge and net.neoforged belong to the loader as well.
• The jar name at the end of a line, here ExamplePlugin-2.1.0.jar, names the plugin file on Paper.
• `Caused by:` is the error behind the error. With several of them, the last one is usually the real cause; here a missing name in the shop config.
• `... 2 more` means the remaining lines are the same as in the block above.

When you report an error to a plugin author, a mod author or us, copy the whole block, from the line with ERROR down to the last at line.

Read the text after the exception name as well. A file name or a message such as because "name" is null points at the setting or file to check.

Most of a log is normal activity. These lines answer everyday questions about the server:

The panel reads the Can't keep up! line too. For five minutes after one appears, the Server health card next to the console shows how many ticks the server was behind.

A crash report is a .txt file in crash-reports. It starts with ---- Minecraft Crash Report ---- and has these parts:

Minecraft server keeps crashing has a table of the common descriptions with the fix for each one.

Crash watch also reads the log after a crash. When it recognises the cause, the Server health card in the Console tab shows Why it crashed last time: the cause in plain words, the steps to take and the log line it is based on.

1. In the Files tab, download logs/latest.log, or the .log.gz file of the day it happened.
2. If the server crashed, also download the newest file in crash-reports.
3. Write down what you changed last and at what time the problem started.
4. Send it all through support. We answer every day from 07:00 to 23:00 Central European Time.

Send the whole file instead of a screenshot or one copied line, because the lines around an error often name the cause. A log contains player names and the addresses players connect from, so share it only with support or the author of a plugin or mod, never in a public channel.