Hi dancehappy, see:

Flash 11.3 doesn't load video in Firefox

Flash 11.3 crashes

Your best solution is downgrade to Flash 10.3, until Adobe release an update for Flash.

thank you

I noted something similar just few moments ago: opening video directly doesn't work at all, Firefox freezes completely for about 30 seconds and when it unfreezes there's only black square instead of video.

On the other hand, Chrome and Explorer work normally and when the video is on the user-page instead of opening it directly, it works fine. Videos on other sites work so it's not about flash this time.

Internet Explorer uses a ActiveX version of Flash, and Chrome comes with its own Flash.

thank you

Apparently there was already some problem with Firefox on YouTube before this one started, so it might be one of those side-effects they usually get when trying to fix the problem.

Ideato: Thank you sooooooooooooo much, that worked perfectly !!!

Hi. For anyone who started to have trouble watching Youtube videos suddenly during or after the third week of July, 2012, it seems they suddenly decided to shift people over to testing html5 scripts that would allow people to watch videos without Flash. But they don't tell you they are doing this.And the script doesn't play well with all browsers and versions. Yay, for thinking things through! Anyhow go to this page if you want to opt out of the testing:

http://www.youtube.com/html5/

Worked like a charm!!!

THANKS!!!! Adobe - Re: Release 11.3 = BOO HISS!