If you installed German (de) Firefox 1.5.0.9 builds on Linux 
and this is your first time installing Firefox, or you have created a 
new profile, you might encounter the following problem:

Bookmarks you create while running Firefox disappear after you quit and restart.

If you encounter this problem you can fix it by doing the following:

1. Uninstall Firefox 1.5.0.9 and delete the profile that was created
with that build (if you do not wish to delete your default profile,
you can try to fix the permissions issue manually, see bug for more
info on which files are effected). For help finding your profile see
http://kb.mozillazine.org/Profile_folder.

2. Go to http://www.mozilla.com/en-US/firefox/all-older.html, install
Firefox 1.5.0.8 (de), and use the new default profile or create a fresh
profile.  For help with managing profiles see
http://kb.mozillazine.org/Profile_Manager.

3. Check for updates with Help->Check for Updates... and then
download and apply the latest update to 1.5.0.9.

4. You should now be updated to the latest version of Firefox 1.5.0.9
and should not have any issues with bookmarks. :-)

NOTE:  This is only a problem with German (de) Firefox
1.5.0.9 builds using the Linux .tar file, and only
effects users that create a new profile with that build.  If you have
an older default profile or created one with Firefox 1.5.0.x or 2.0,
you should not experience this problem.

We've temporarily removed the German (de) Firefox 1.5.0.9 builds from the 
download servers so that new users will not be affected by this issue. 
Anyone downloading 1.5.0.8 can either manually check for updates (as 
described above) or wait a few days for the update to 1.5.0.9 to 
automatically download.

See bug https://bugzilla.mozilla.org/show_bug.cgi?id=364599 for more
info.