This can be a problem with the file places.sqlite that stores the bookmarks and the history. * http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox ---- If you posted with Firefox 4 then you should check the user agent that currently identifies you as suing Firefox 3.0.13: * Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.13) Gecko/2009073022 Firefox/3.0.13 (.NET CLR 3.5.30729) FBSMTWB See: * [[Web sites or add-ons incorrectly report incompatible browser]]