""This has happened to me twice, the first time erasing Firefox
settings, and the second time erasing gnome-terminal settings. Both
cases were caused by a kernel panic locking up the system. Also,
both times the program whose settings were affected was in use
during the kernel panic."
"This has been a wide-spread problem, particularly for Ubuntu
users testing the new Jaunty alpha releases. It manifests itself
after a system crash, where open files will simply be emptied and
erased. It is particularly prevalent in users' settings files, such
as those used for GNOME or KDE. Fortunately, there cause of the bug
is relatively well-known, as kernel developer Theodore Ts'o
explains in his detailed comment:"