Try using this extension to force compatibility. https://addons.mozilla.org/en-US/firefox/addon/add-on-compatibility-reporter/ Also see this: * '''weisguys01:''' ''As an alternative, I started Safari (on same PC) just to try anything to register my Garmin. It required me to download a new exe for the plug-in. Ran install, which required closing Safari. Install automatically started default browser (Firefox) which now works perfectly.'' Taken from: https://support.mozilla.com/en-US/questions/829905 Check and tell if its working.