A possible cause is 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 *https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file You can also try to repair the places database with this extension: *https://addons.mozilla.org/firefox/addon/places-maintenance/ ---- *http://kb.mozillazine.org/Lost_bookmarks