Yeah me too, ive been trying to fix it for several months. Its a hopeless timewaster. Firefox developers are too busy with thier fast release cycle, adding fancy features to keep up with Google chrome, so they just leave broken things broken. I use opera now for videos.

First, try to use Flash 11.5, it has alot of the bugs that were in Flash 11.3 fixed and is more secure anyway.

After doing that, you should also check if you have flash 32 bit or 64 (waterfox is not a supported product, it's a community effort, so we are limited in how much help we can be)

Have now progressed, but there remains a problem to be solved. I uninstalles Flash. I then disabled anti-virus, firewall, spamfilter and vulnerables. Installes flash (which it found the latest version to be the correct one to install), 11-5-502-110. When I wen tinto WATERFOX, it worked perfectly.

When i restarted the desktop later, waterfox failed to display using Flash.

If I run Find Flashplayer version, (helpx.adobe.com/flash-player/kb/find-version-flash-player.html) it identifies that flash is installed........ .

This sequence has now occurred twice (that is uninstallin then reinstalling Flash with firewall etc. disabled).

How do I now determine if the is a problem for Adobe or within Waterfox? No doubt a dud registry entry somewhere?

Eric