Same for me, youtube downloads have stopped working 3 days ago. Video download from other sites are still working but I'm mainly using it with YouTube.
Check out version 4.5 released today. Also a lot of older versions were updated to handle changes on download sites!
The fact is that Google is constantly fighting to download content, as it sees it as a violation of copyright. In this regard, some downloaders stop their work, while others change the order of interaction. I also do not get a save button. And even having a premium subscription - I can't upload a clip and download the broadcast.