As described in 4398496 (and several related bugs), the Unix prefs implementation (FileSystemPreferences) attempts to create a system prefs directory at run time if none exists. As of Mantis (1.4.2) this only happens if the application actually attempts to use systems prefs, so it should not be a problem in practice. Nevertheless, this behavior does not seem reasonable. Creating the system prefs directory is part of the installation of the Java platform. A program attempting to access System prefs will generally not have the privileges required to create the directory, so the attempt will typically fail. Rather than making such an attempt, the application should simply operate with very limited access to system prefs (e.g., default value will always be returned by queries).