https://www.youtube.com/watch?v=MhJbdV07avs
“its caused by the DownloadHelper add-on in Firefox, disable it and it will work again”
“I fixed mine just now fyi. I went into account settings and hit “verify”. It went straight to “upload video’ mode, so I did and now it is working!!! Like it is supposed to!!!! Amazing!!”
“Ya seems to be a Firefox thing, works ok in IE”