Troubleshooting

Most problems that people have are due to one or more of the following reasons:

Windows troubleshooting

If

You see an error message like:

Could not find the main class: Main.  Program will exit.
========================================
Warning: lib\minecraft.jar not found.
Did you read instructions / download it?
========================================

Then

You didn't read the instructions, and download then install the minecraft.jar file.

To fix

Go back to the instructions, download minecraft.jar as instructed and place it in the correct directory.

If

You see an error like:

ERROR: 32-bit Java 6 not found!
Please download and install from java.com

Then

You do not have the correct version of java installed, or it cannot be found automatically.

To fix

This needs 32 bit Java 6. You need to download and install it from: http://java.sun.com/javase/downloads
Look for the file labeled: "Java SE Runtime Environment (JRE)", click the download button.
Select "Platform: Windows" from the next download page that appears (note: Do not select 64 bit or Itanium versions, these will not run the wrapper)
Download it, install it.

If after installing the correct version, or if it is installed but cannot be found automatically due to it being in a non-standard location, open the run.bat in a text editor and change the line that reads:

set JAVA6="auto"

to read

set JAVA6="C:\MyPath\bin\java.exe"

(change "C:\MyPath" to your actual java installation's path)

Mac OSX Troubleshooting

If

You see an error like:

-bash: ./minecraft-osx.sh: Permission denied

Then

The minecraft-osx.sh file does not have execute permission.

To fix

Run the following command:

chmod +x minecraft-osx.sh

If

You see an error like:

./minecraft-osx.sh: line 12: /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home/bin/java: No such file or directory

Then

Your mac doesn't have the Java 6 interpreter installed.

To fix

You need at least OS 10.5 with the Java 6 packs applied (if you apply system updates, you should have this, otherwise look for the Java 6 downloads from the Apple site.

If

You see an error like:

Exception in thread "main" java.lang.NoClassDefFoundError: com/mojang/minecraft/MinecraftApplet

Then

You didn't read the instructions, and download then install the minecraft.jar file.

To fix

Go back to the instructions, download minecraft.jar as instructed and place it in the correct directory.

Linux Troubleshooting

Running under linux

You will need to modify the minecraft-osx.sh file to point to your local java interpreter.

Focus / mouse clicking issues

There can be some weird interactions between the windows managers and the java windows that make java think it has lost focus whenever you click. Very rarely this may not happen on some combinations of linux+distro+x11+wm, but for most linux users, this will be a problem. In this case you may want to take a look at the Don't lose focus hack, which may solve this problem for you.

/dev/input/event ownership problems

If you see an error like:

Failed to open device (/dev/input/event0): Failed to open device /dev/input/event0 (13)

This means that the current user doesn't have permission to access the direct input devices.

sudo chmod go=u /dev/input/event*

Should fix the problems here.