Minecraft Crash Log Analyzer

Paste any Minecraft log or crash report. This page checks 210 known error signatures and tells you which mod broke, what it is missing and where to get the right build. It runs entirely in your browser — your log is never uploaded.

Paste your log or crash report

Works with crash-report.txt, latest.log, launcher logs and plain Java stack traces. Paste the whole file, or just the part around the first Exception.

Ctrl+Enter also runs it
Try a sample:

Private by design. The analyzer is one JavaScript file running on your machine. Nothing you paste is sent to a server, stored or logged — you can disconnect after the page loads and it still works.

What this tool detects

All 210 errors
Corrupted filesCorrupted Config File (NightConfig ParsingException: Not enough data available)Find the line starting with 'ConfigLoadingException: Failed loading config file' near the top of your crash reCorrupted filesCorrupted Mod Config File (NightConfig ParsingException)Read the `ConfigLoadingException` line near the top of your crash report to find the exact `.toml` filename (fCorrupted filesCorrupted Mod Config File (NightConfig ParsingException: Invalid character)Find the line in your crash report starting with `Failed loading config file` to see the exact `.toml` filenamCorrupted filesFabric Startup Crash: WindowsException (AccessDeniedException or NoSuchFileException)Find the `Caused by: java.nio.file.NoSuchFileException:` or `AccessDeniedException:` line in your crash log anCorrupted filesJsonSyntaxException: Expected BEGIN_OBJECT but was STRING at line 1 column 1Look at the crash report lines directly underneath `at com.google.gson.Gson.fromJson` to identify what was reaCorrupted filesUnable to Launch: ClassNotFoundException FMLTweakerOpen your launcher's root directory (such as `.minecraft` or `MultiMC`), navigate to `libraries/net/minecraftfCorrupted filesjava.nio.file.NoSuchFileException During Fabric or Iris StartupRead the exact file path after `Caused by: java.nio.file.NoSuchFileException:` in your crash log to identify wCorrupted fileszip END header not found — a mod jar is corrupted or half-downloadedDelete that jar and download it again — the file is incompleteData packsFailed to load registries due to above errorsOpen your Minecraft instance folder, navigate to the logs folder, and open latest.log (not the crash report) iDuplicate modsDuplicate mods found — the same mod is installed twiceTwo jars of the same mod, usually one with (1) in the nameExit codesExit code -1073740791 (0xC0000409) — stack buffer overrunA native library crashed, not Java code — almost always the GPU driverExit codesExit code -1073741819 (0xC0000005) — access violationSame family as EXCEPTION_ACCESS_VIOLATION — a native crash

Browse by what went wrong

210
Missing dependencies7A mod asks for another mod or library that is not installed, or not at the version it needs.Wrong Minecraft version28The mod was built for a different Minecraft release than the one you are launching.Wrong mod loader3A Forge jar in a Fabric instance, or the other way round. The file names look the same.Mixin failures10A mod could not patch the game code it expected to find.Out of memory8The game ran out of heap, metaspace, or could not reserve what you asked for.Graphics and drivers8OpenGL, shader and driver crashes, including the ones that kill the process outright.Java version problems7The wrong Java release for the Minecraft version or the loader you are running.Exit codes5What each number the launcher prints actually means, and where to look next.World and tick crashes7Ticking entity, missing registry entries and the crashes that happen inside a save.Mod conflicts48Two mods fighting over the same game code, or one mod breaking on another.Server setup7EULA, client-only mods on a server, and the server launcher itself.Connection problems11Ports, timeouts, outdated client or server, and download failures.Corrupted files8Half-downloaded jars and archives the loader cannot read.Duplicate mods1The same mod installed twice, usually one copy with (1) in the name.Launcher problems18Crashes that happen before the game starts, inside the launcher itself.Reading the log20Lines that look like the cause but are only wrappers around the real error.Resource packs4Packs the game refuses to load.Data packs2Recipes, loot tables and advancements that fail to load.Performance3Freezes, stutter and watchdog shutdowns that are not a hard crash.Account and login5Authentication failures between the launcher and Mojang.

Exit codes

All exit codes
1The game stopped itself. The reason is higher up the log.-1The JVM died before it could write a crash report.0A clean exit — if the window vanished, nothing crashed.137Killed with SIGKILL, usually the Linux out-of-memory killer.143Stopped with SIGTERM — something asked it to shut down.-805306369The JVM was told to quit while it was busy.-1073740791Stack buffer overrun in native code.-1073741819Access violation in native code.-1073741515A required DLL could not be found.

Questions people ask

Where do I find my crash report?
Open your Minecraft folder (.minecraft on the client, the server folder on a server). Crash reports are in crash-reports/ and are named by date. The rolling log is logs/latest.log. Launchers such as Prism, MultiMC and ATLauncher keep a copy per instance.
Should I paste the whole file?
Yes if you can — the version, loader and mod list at the top help the analysis. If the file is huge, the part from the first Exception or Caused by: down to the end is enough.
Is my log uploaded anywhere?
No. The analyzer is a JavaScript file that runs on your machine. Nothing you paste leaves the browser, and nothing is stored. You can turn off your connection after the page loads and it still works.
It says my mod is missing a dependency. Which file do I download?
The log names both the mod and the version range it needs. Download the build that matches your exact Minecraft version and loader — a 1.20.1 Fabric jar will not load on 1.20.4 or on Forge, even when the file name looks the same.
Why did it not recognise my error?
The rule set covers the signatures we have seen in real reports. If nothing matched, the result box still names the deepest non-vanilla package in the stack trace — that is the first mod to look at.
What does "exit code 1" mean on its own?
Only that the game stopped itself. The reason is further up the log. Paste the whole file and the analyzer finds the line that matters.