Hello Daniel.

Please contact the add-on author for support.

To disable or uninstall the add-on, to into Tools > Add-ons > Extensions.

I've tried this and still the same problem. Uninstalled, same problem. Internet Explorer has the site advisor showing so this may be FireFox related

Just an update. Fire Fox is just like all the others!!! Block other programs in favor of yours i.e. WOT site advisor add on from Mozilla Vs McAffee site advisor. WOT works fine. With all the security up dates for Fire Fox, maybe it's time to return to IE

WOT site advisor add on is not from Mozilla. It's a 3rd party addon like McAfee is.