Plugins are added by external software and not under control of Firefox and can only be disabled unlike extensions that are installed in Firefox. You will have to go to the program that installed the plugin to remove it from Firefox. You can find the installation path of all plugins on the <b>about:plugins</b> page. *http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins *http://kb.mozillazine.org/about:plugins *http://kb.mozillazine.org/about:config See also "Manually uninstalling a plugin": *https://support.mozilla.org/kb/Troubleshooting+plugins