I saw a a previous post with a similar problem (https://support.mozilla.org/en-US/questions/1008744?esab=a&as=aaq) , but it's not for the same sort of content, and the answers did not help me. I'm trying to view a virtual tour on a website, and I don't know why it's not showing up, but it does if I view it directly. There is absolutely no indication as to //what// plugin is missing, and where I can get it. I am using the latest versions of Firefox and Flash, on Win 8.1. You can find it here: http://www.autopano.net/wiki-en/action/view/Panotour_Tutorials_-_Create_a_simple_virtual_tour_and_upload_it_on_Google_Drive#Finished_Tour It works on every other browser. The full link to the content directly is here, which /DOES/ work in FF: https://49bc6130e8cd1d9c5acf43941b125e6652644cc2.googledrive.com/host/0B21ztMIr_KkXdTNvcHNOYjNlVGc/index.html I asked for the embed code that was used, which is <embed src="https://49bc6130e8cd1d9c5acf43941b125e6652644cc2.googledrive.com/host/0B21ztMIr_KkXdTNvcHNOYjNlVGc/index.html?html5=only" width="700" height="500"></embed> Why can't I view the content? Ps: Your troubleshooter add-on doesn't have a verified author, that's a bit silly.