PLEASE READ THIS: Do not give Easy Youtube Video Downloader Express a bad review because of the current problem. This awesome addon will be back online soon! I wrote to Dishita and got a terrific reply back:

"I am aware of the recent code changes by Youtube that resulted in the 'No Button Display Issue'. This happens because Youtube tries to block downloaders via code changes. I have already generated a fix which has been uploaded to the Firefox Team for review and approval. It should be approved very soon. It will then get published and the addon should get auto-updated to v16.10."

I have been using the pro version for five years and Dishita has been nothing but stellar in his constant support and upgrades. He cares about his addon and strives to stay ahead of Youtube's constant efforts to block him and others from having downloaders that work.