Firefox should not lose information like bookmarks when it updates. Even if you Reset|Refresh Firefox it retains some of the information, and should still not lose bookmarks. Possibly somehow Firefox has lost track of the profile where this information is stored. Have a search on the computer to see if you can find any files called ''places.sqlite'' one of those will be your current almost empty database, an other may be the old one you need. *see also http://kb.mozillazine.org/Show_hidden_files_and_folders There is also a possibility the file exists but is corrupt, however that is less likely because of all the other items that have disappeared.