Start Firefox in <u>[[Safe Mode]]</u> to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes). *Don't make any changes on the Safe mode start window. *https://support.mozilla.com/kb/Safe+Mode *https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes ---- Another 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.com/kb/Bookmarks+not+saved#w_places-database-file