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In YOUTUBE videos are not playing


I have recently upgraded my browser from Firefox 3.6 to Firefox 4 beta version. Now I find that videos are not playing in YOUTUBE website. A black window appears.

Additional System Details

Sites Affected


Installed Plug-ins

  • Picasa plugin.
  • iPhoto6
  • The Google Earth Plugin allows you to view 3D imagery and terrain in your web browser.
  • Java Plug-In 2 for NPAPI Browsers
  • Shockwave Flash 10.1 r102
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in web pages. For more information, visit the QuickTime Web site.


  • User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0b9) Gecko/20100101 Firefox/4.0b9

More Information

Metal-Mighty 0 solutions 1 answers

Try to install Adobe Flash Again. If this doesn't works, check in you addons manager there isn't any plugin interfering with flash animations/videos

  • Top 10 Contributor
  • Moderator
10746 solutions 96695 answers

That Firefox 4 beta 9 version is outdated.
Make sure that you update to the latest Firefox 4 RC2 version.

Clear the cache and the cookies from sites that cause problems.

  • "Clear the Cache": Firefox > Preferences > Advanced > Network > Offline Storage (Cache): "Clear Now"
  • "Remove the Cookies" from sites causing problems: Firefox > Preferences > Privacy > Cookies: "Show Cookies"

You can also try to change the protocol in the YouTube links from http: to a secure https:

remymel 0 solutions 1 answers

1. START any youtube video that's not working. 2. right-click on face of video. 3. click SETTINGS. 4. UNCHECK "Hardware Acceleration"

ekovanis 0 solutions 1 answers

Helpful Reply

I was having this problem and solved it by going into the Add-ons area, clicking on the Plugins menu item and disabling Shockwave Flash 11.3.300.257. Maybe that will help.

esgt 0 solutions 1 answers

Shokweave is disabled by me now videos are playing but speedbit video download is now not working