= Troubleshooting Linux =

For generic, non operating system specific troubleshooting information, check the [[Troubleshooting]] page.

== I can't find !WorldPainter after installation? How do I start !WorldPainter? ==

If you installed the .deb or .rpm package, !WorldPainter is installed in `/opt/worldpainter`. Try starting it from a terminal window with the command:

{{{
/opt/worldpainter/worldpainter
}}}

If you used the installer (the .sh package), or an installerless archive, then you specified the installation directory when you installed the program. Try executing the worldpainter command from the installation directory using something like this from a terminal window:

{{{
/path/to/worldpainter/worldpainter
}}}

== Headless runtime error or !NoClassDefFoundError

If !WorldPainter does not start, and gives one the following errors on the console or in the log file:

{{{
The Java runtime (...) is headless.
}}}

or:

{{{
Exception: java.lang.NoClassDefFoundError thrown from the UncaughtExceptionHandler in thread "AWT-EventQueue-0"
}}}

then this means that !WorldPainter can't find a complete Java runtime with GUI support. Some distributions, such as Fedora, have a "headless" Java runtime environment installed by default, which only supports console applications, but not graphical user interfaces.

If this is the case, then you need to manually install a complete Java runtime, either a JRE or a JDK. For Fedora for example, the command for this would be:

{{{
sudo dnf install java-21-openjdk
}}}

For other distributions a similar command will be available. For the Java version it is recommended to use the latest LTS version.

== !WorldPainter won't start or is not usable any more ==

 * If you made a change (such as installing custom brushes or a plugin, or changing a preference) and now !WorldPainter won't start or is not usable any more, try using [SafeMode WorldPainter Safe Mode]. It will allow !WorldPainter to start and operate again, allowing you to undo the change you made, or confirm that the change was what caused the problem so you know to undo it.
 * If that does not work, try resetting the preferences by deleting the !WorldPainter configuration file ({{{~/.worldpainter/config}}} or {{{~/.local/share/worldpainter/config}}}).