Well, tried again a few years since the first attempt. This time I managed to download two files from Youtube before it conked out and died. Only this time it did something to Firefox I've never experienced before. It stalled out everything, so I quit Firefox. Or so I thought.

It never quit at all, but instead of the application showing "Application Not Responding", I had to Force Quit. But even upon doing so, despite the window closing, Firefox remained open. Except no active windows could be open. Further attempts to quit via the drop down menu resulted in nothing as well. I attempted another Force Quit, and this time it responded.

I reopened the application, attempted once again to download from YouTube and the extension froze trying to create another download link.

I'll stick with ClibGrab, never any problems with it. These so-called YouTube download extensions never work.