Troubleshooting

Minecraft Troubleshooting Guide: Every Error and Fix

Complete Minecraft troubleshooting hub. Find fixes for crashes, connection errors, performance issues, mod conflicts, server problems, and launch failures.

8 min read12 sectionsJava & Bedrock1.21

This hub collects every Minecraft troubleshooting guide we have published. Use the categories below to jump to the section that matches your problem. Each guide contains the exact error message, a quick fix, step-by-step diagnosis, and answers to frequently asked questions.

All guides target Minecraft Java Edition 1.21+ unless stated otherwise. Server-specific guides assume Paper or Spigot. Client-specific guides cover the official launcher and popular third-party launchers.

How to Use This Guide

Find your error message or symptom in the categories below.
Click the link to go to the full guide.
Follow the Quick Fix first. If that does not resolve it, work through the Step-by-Step Diagnosis.
If your issue is not listed, check the server or client logs for the exact error message and search for it on this page.

Crashes Issues

How to Fix java.lang.OutOfMemoryError in Minecraft - Complete guide to fixing java.
How to Fix Minecraft Exit Code -1 - Fix Minecraft exit code -1 (process crashed).
How to Fix Minecraft Exit Code 1 - Fix Minecraft exit code 1 on launch.
How to Fix java.lang.NullPointerException Crash in Minecraft - Fix NullPointerException crashes in Minecraft clients and servers.
How to Fix Pixel Format Not Accelerated in Minecraft - Fix the 'Pixel Format Not Accelerated' OpenGL error in Minecraft.
How to Fix Ticking Entity Crash in Minecraft - Fix 'Ticking entity' crash errors in Minecraft servers and clients.

Connection Issues

How to Fix Connection Timed Out in Minecraft - Fix Minecraft 'Connection Timed Out' errors.
How to Fix Failed to Login: Bad Login in Minecraft - Fix the 'Failed to login: Bad login' or 'Invalid session' error in Minecraft multiplayer.
How to Fix Connection Refused in Minecraft - Fix 'Connection Refused' errors when joining a Minecraft server.
How to Fix Connection Timed Out in Minecraft - Fix Minecraft 'Connection Timed Out' errors.
How to Fix Outdated Server in Minecraft - Fix the 'Outdated server' or 'Outdated client' message in Minecraft multiplayer.
How to Fix "You Are Not Whitelisted on This Server" - Fix 'You are not whitelisted on this server' in Minecraft.
How to Fix Secure Profile Required in Minecraft - Fix 'Multiplayer is disabled' and 'Secure profile required' errors in Minecraft.
How to Fix the io.netty.channel.AbstractChannel Error - Fix io.

Performance Issues

How to Fix Lag on a Minecraft Server (2026) - Complete guide to diagnosing and fixing Minecraft server lag, TPS optimisation, entity management, chunk loading, JVM tuning and network latency fixes.
Fix Chunk Loading Errors in Minecraft Servers - Resolve chunk loading errors and corrupted chunks on Minecraft servers, symptoms, causes, region file repair and prevention strategies.
How to Diagnose & Fix TPS Drops on Minecraft Servers - Step-by-step guide to diagnosing and fixing TPS drops on Minecraft servers, profiling with Spark, entity culling, tick analysis and Paper optimisation.
Fix High CPU Usage on Minecraft Servers - Diagnose and fix high CPU usage on Minecraft servers, Spark profiling, tick analysis, entity optimisation, garbage collection tuning and hardware considerations.
How to Fix Low TPS and Server Lag in Minecraft - Fix low TPS (ticks per second) and server-side lag in Minecraft.
How to Fix High RAM Usage in Minecraft - Fix excessive RAM usage in Minecraft clients and servers.
How to Fix Minecraft Using Too Much CPU - Fix Minecraft high CPU usage on servers and clients.
How to Fix Chunk Loading Lag in Minecraft - Fix slow chunk loading and chunk lag in Minecraft servers and clients.
How to Fix Entity Lag in Minecraft - Fix entity-related lag and TPS drops in Minecraft servers.
How to Fix Minecraft Stuttering and Micro-Freezes - Fix Minecraft stuttering, micro-freezes, and frame drops on the client.

Mods Issues

How to Fix Mods Not Loading in Minecraft - Fix Minecraft mods not loading or not appearing in-game.
How to Fix Forge Crash on Startup in Minecraft - Fix Minecraft Forge crashing on startup.
How to Fix Incompatible Mods on Fabric in Minecraft - Fix Fabric mod incompatibilities, mixin conflicts, and version errors.
How to Resolve Mod Conflicts in Minecraft - Systematic guide to finding and resolving mod conflicts in Minecraft.
How to Fix Missing Mod Dependencies in Minecraft - Fix 'Missing dependencies' errors for Minecraft mods.

Server Issues

Minecraft Server Not Starting? Here's How to Fix It - Troubleshoot a Minecraft server that won't start, Java version errors, port conflicts, corrupted files, missing EULA and common startup failures explained.
How to Fix & Recover a Corrupt Minecraft World - Recover a corrupted Minecraft world, repair level.
Fix Player Data Loss on Minecraft Servers - Recover and prevent player data loss on Minecraft servers, inventory rollback, playerdata file recovery, NBT repair and backup strategies.
Minecraft Server Crashes on Startup, Full Fix Guide - Fix Minecraft server crashes on startup, read crash logs, resolve Java errors, fix corrupt worlds, remove broken plugins and diagnose memory issues.
How to Fix a Minecraft Server That Will Not Start - Fix a Minecraft server that refuses to start.
How to Fix World Corruption in Minecraft - Fix corrupt Minecraft worlds that crash or have missing chunks.
How to Fix Chunk Corruption in Minecraft - Fix corrupt chunks in Minecraft: void holes, invisible blocks, and crashes on chunk load.
How to Fix Player Data Corruption in Minecraft - Fix corrupt player data files (.
How to Fix Whitelist Not Working in Minecraft - Fix Minecraft whitelist not blocking players, not saving entries, or not syncing across proxy servers.
How to Fix OP Permissions Not Working in Minecraft - Fix operator permissions not working in Minecraft servers.

Launch Issues

How to Fix Minecraft Not Launching - Fix Minecraft refusing to launch or disappearing after clicking Play.
How to Fix Black Screen on Launch in Minecraft - Fix Minecraft launching to a black screen.
How to Fix Minecraft Launcher Crashes - Fix the Minecraft launcher crashing, not opening, or freezing.
How to Fix Java Not Found in Minecraft - Fix 'Java not found' or 'Unable to locate Java' errors in Minecraft.
How to Fix 32-Bit Java Issues in Minecraft - Fix Minecraft memory limits and crashes caused by 32-bit Java.

Other Issues

How to Fix 'Can't Keep Up' on a Minecraft Server - Learn why your Minecraft server says 'Can't keep up! Is the server overloaded?' and how to fix it with tick optimisation, JVM flags and plugin audits.
Fix 'Failed to Verify Username' in Minecraft - Resolve the 'Failed to verify username' error in Minecraft caused by Mojang session server issues, VPNs, online-mode settings and authentication problems.
Fix 'Out of Memory' Error on Minecraft Servers - Resolve java.
How to Fix Plugin Compatibility Issues (Minecraft) - Resolve Minecraft plugin compatibility issues, version mismatches, API breaks, dependency conflicts, soft-depend errors and class loading problems.
Fix Java Version Errors on Minecraft Servers - Resolve Java version errors on Minecraft servers, UnsupportedClassVersionError, install the correct JDK, manage multiple Java versions and configure your start script.
How to Fix Whitelist Not Working in Minecraft - Fix Minecraft whitelist not blocking players, not saving entries, or not syncing across proxy servers.
Fix Permission Denied Errors on Minecraft Servers - Resolve permission denied errors on Minecraft servers, LuckPerms setup, permission nodes, inheritance, file system permissions and op level configuration.
Fix Nether Portal Linking Issues in Minecraft - Fix Nether portal linking problems, portals connecting to the wrong destination, portal math, coordinate conversion, multiworld plugin conflicts and manual linking.
Fix Mobs Not Spawning on Your Minecraft Server - Troubleshoot and fix mobs not spawning on Minecraft servers, mob caps, spawn conditions, gamerules, Paper spawn limits, light levels and difficulty settings.
Fix 'Disconnected' / 'Kicked' Errors in Minecraft - Troubleshoot and fix Minecraft disconnection and kick errors, timeout kicks, anti-cheat false positives, packet errors, server-side kicks and network stability.
How to Fix "Failed to Bind to Port" in Minecraft - Fix the 'Failed to bind to port' IOException when starting a Minecraft server.
How to Fix "Internal Exception: java.io.IOException" - Fix 'Internal Exception: java.

General Troubleshooting Steps

If your specific error is not listed above, follow this general diagnostic process:

Read the log. Every Minecraft error is logged. Check .minecraft/logs/latest.log (client) or logs/latest.log (server) for the first ERROR or FATAL line.
Read the crash report. If a crash report was generated in crash-reports/, the top of the file contains the exception and a description of what failed.
Search for the exact error message. Copy the first line of the exception (like java.lang.NullPointerException) and search for it. Include "Minecraft" and your version number.
Test without mods. Move the mods/ or plugins/ folder and test. If the problem disappears, a mod or plugin is the cause.
Test with a fresh profile. Create a new launcher profile or a new server directory. If the problem disappears, something in your existing configuration is corrupt.
Update everything. Java, GPU drivers, the game version, mod loader version, and all mods/plugins. Many issues are fixed in updates.

When to Ask for Help

If you have followed the relevant guide and the problem persists:

Collect your crash report, latest.log, and a list of installed mods/plugins.
Note your Java version (java -version), Minecraft version, and mod loader version.
Post on the server's Discord, the Minecraft subreddit, or the mod/plugin's issue tracker with all of this information.

FAQ

How do I find my Minecraft logs?

Client: .minecraft/logs/latest.log. On Windows, press Win+R and type %appdata%\.minecraft\logs. On macOS: ~/Library/Application Support/minecraft/logs. On Linux: ~/.minecraft/logs.

Where are crash reports stored?

Client: .minecraft/crash-reports/. Server: crash-reports/ in the server directory. Files are named with the date and time of the crash.

Should I use Forge or Fabric?

For Minecraft 1.21+, Fabric generally has better performance and faster updates. Forge (and its successor NeoForge) has a larger mod library for older versions. Choose based on which mods you want to use.

What Java version do I need?

Minecraft 1.21+ requires Java 21. Minecraft 1.17-1.20 requires Java 17. Minecraft 1.16 and older requires Java 8. Always use 64-bit Java.

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Questions about Minecraft Troubleshooting

What does Minecraft Troubleshooting come down to?

This hub collects every Minecraft troubleshooting guide we have published.

How much does Minecraft Troubleshooting actually need?

How to Fix Lag on a Minecraft Server (2026) - Complete guide to diagnosing and fixing Minecraft server lag, TPS optimisation, entity management, chunk loading, JVM tuning and network latency fixes.