Hi, You can try to '''Disable''' or '''Remove''' the '''Extension''' corresponding to the sidebar feature in '''Tools''' ('''Alt''' + '''T''') > '''Add-ons'''. [https://support.mozilla.com/en-US/kb/Troubleshooting%20extensions%20and%20themes Troubleshooting] [https://support.mozilla.org/en-US/kb/Uninstalling%20add-ons Uninstalling add-ons] [http://kb.mozillazine.org/Uninstalling_toolbars Uninstalling toolbars] [https://support.mozilla.org/en-US/kb/Using%20extensions%20with%20Firefox Using extensions] [https://support.mozilla.org/en-US/kb/Customizing%20Firefox%20with%20add-ons Customizing Firefox] If problems persist you can reset Firefox and start afresh. The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: ''This will cause you to lose any Extensions, Open websites, and some Preferences.'' To Reset Firefox do the following: #Go to Firefox > Help > Troubleshooting Information. #Click the "Reset Firefox" button. #Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish. #Firefox will open with all factory defaults applied. Further information can be found in the [[Reset Firefox – easily fix most problems]] article. Did this fix your problems? Please report back to us!

You may have enabled the Social features in Firefox.<br /> You can check the value of the social.enabled pref on the <b>about:config</b> page. *http://kb.mozillazine.org/about:config *http://blog.mozilla.org/futurereleases/2012/07/06/bringing-social-to-firefox/ *http://blog.mozilla.org/labs/2012/03/experimenting-with-social-features-in-firefox/