Addons that are not signed have been disabled in the latest version of Firefox for security purposes. To enable this addon again, please do the following: #Type <code>about:config</code> in the address bar #Click the ''I'll be careful'' button #Locate the <code>xpinstall.signatures.required</code> boolean #Change the value on this preference to <code>false</code> '''Note: '''You may need to restart Firefox in order for the changes to take effect. '''Warning: '''Doing the above steps may present a security threat. Please use with caution and at your own risk. For more information about addon signing, please refer to this Mozilla support article. *[[Add-on signing in Firefox]]