Please see solution in http://kb.mozillazine.org/Problematic_extensions for "McAfee Site Advisor". (Windows): For best results you should uninstall '''McAfee Site Advisor''' from Control Panel > add/change programs (Programs and Features). Reboot the system. Then Reinstall from http://www.siteadvisor.com/ and reboot the system. When installing refuse other suggested (crapware) applications. <br><small>Please mark "Solved" one answer that will best help others with a similar problem -- hope this was it.</small>