DownloadHelper not working with Youtube - solution
1) press: Ctrl+Shift+Del to go to History cleaning. 2) select timeframe: all 3) mark: Cookies, Browser Cache, Active Logins, Offline Data, Site Settings. (you can also mark Search History but it is not neccessary) 4) press: Clear button.
It solved the problem of downloading 0kb files instead of YouTube videos.
(with Firefox 25.0, DownloadHelper 4.9.21)
Additional System Details
- Google Update
- Shockwave Flash 11.7 r700
- Next Generation Java Plug-in 10.25.2 for Mozilla browsers
- NPRuntime Script Plug-in Library for Java(TM) Deploy
- Adobe PDF Plug-In For Firefox and Netscape
- User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:26.0) Gecko/20100101 Firefox/26.0
If you do not want to clear anything from the search history you can also press Shift+Ctrl+P to go to private mode. (DownloadHelper works fine in private mode even when it does not work in normal mode)
Thanks for letting everyone know that you found a couple of solutions for problems with DownloadHelper at YouTube. I take it that you meant the "Video DownloadHelper" Firefox extension available here:
Another good place to post this information would be on the above webpage, by using the "Write a review" button.
I'm going to close this question and mark it "off-topic" since you weren't actually asking for help with Firefox. Thanks again.
Modified by AliceWyman