Thread:Ravenclaw Prefect/@comment-80.84.56.61-20141011162747/@comment-4189484-20141011183800

Well, I guess first and foremost, go to Tools > Extensions and make sure it is enabled. Also, the icon only appears when you're on a Nico video. For instance, it should appear when you click on this:

http://www.nicovideo.jp/watch/sm19193113

I hear you can't download community videos, but I don't know if that means the icon doesn't appear or it won't download the mp3/video. If all else fails, uninstall and reinstall the add-on, and/or restart your computer.