Ok I can comment, like, favorite now! For anyone who had the same issue after the last youtube update and video download helper "on"
"Here is a workaround that works for me (until a new version of VDH is
released):
- Open a new tab and type in the URL bar "about:config" (without the quotes)
- Search for parameter "dwhelper.yt-visitor-cookie", double click on it and
change the value from "remote" to "keep"
- Reload the YouTube page
- You should now be able to use the Like/Unlike buttons" (fix by
mig)
After the youtube's latest update there was a cookie issue that they fixed for the downloading of videos that were giving a blank archive. This fix caused a conflict between the youtube functions above and VDH while it was active.