No, you shouldn't lose your bookmarks if you update. Your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks and other personal data. * http://kb.mozillazine.org/Profile_folder_-_Firefox ---- If you get problems with the bookmarks a possible cause is a problem with the file places.sqlite that stores the bookmarks and the history.<br /> Such problems can be caused by Firefox using the native SQLite provided by the OS on a Mac. *http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox *http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox