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Why do certain videos not display or play in my browser since i updated firefox to 5


I recently downloaded firefox5 and now my videos on my website do not display in my browser on certain pages. They are the videos imbeded into a wordpress 3.2.1 site using the Quicktime Embed 2.0 plugin. The videos display fine on my husbands PC with the firefox4. I use QuickTime X on a MAC. Why are these videos not displaying or playing since the firefox update?I have provided the specific pages where the videos do not display in my browser below. They do display in Safari

Additional System Details

Sites Affected


Installed Plug-ins

  • Office Live Update v1.0
  • iPhoto6
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in web pages. For more information, visit the QuickTime Web site.
  • 4.0.51204.0
  • DivX Web Player version
  • DivX OVS Helper Plug-in
  • The Flip4Mac WMV Plugin allows you to view Windows Media content using QuickTime.
  • Java Plug-In 2 for NPAPI Browsers
  • Shockwave Flash 10.3 r181


  • User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:5.0.1) Gecko/20100101 Firefox/5.0.1

More Information


Hasan 477 solutions 5600 answers

-> click Firefox button and click Exit

Start Firefox in Safe Mode by Holding down the Option key while starting your Mozilla application.

As an alternate method, go to Utilities (in the Applications folder) and open Terminal, then run:

    /Applications/Firefox.app/Contents/MacOS/firefox-bin -safe-mode 

Firefox will open up with just basic Firefox. Now do this:

-> Update ALL your Firefox Plug-ins https://www.mozilla.com/en-US/plugincheck/

-> Right-click on Tab Strip and unselect All Unwanted/Incompatible Toolbars

-> click Firefox button, go to History Menu and click Clear Recent History... -> Time range to clear: select "EVERYTHING" -> click Details (small arrow) button -> place Checkmarks on Cookies, Cache -> click Clear Now

-> go to Content section -> place Checkmarks on:

1) Block Pop-up windows 2) Load images automatically 3) Enable JavaScript

-> go to Privacy section -> History section -> Firefox will: select "Remember History"

-> go to Advanced section -> Network -> Offline Storage (Cache): click Clear Now button

-> Click OK on Options window

-> click the Firefox button, click Add-ons -> Extensions section -> REMOVE All Unwanted/Suspicious/Incompatible Extensions (Add-ons)

-> click the Firefox button, click Add-ons -> Appearance section -> REMOVE All Unwanted/Suspicious/Incompatible Themes (Persona)

-> Restart Firefox

You can enable your Known & Trustworthy Add-ons and Themes later. Check and tell if its working.

Question owner

Videos now display on 2 of the 3 pages, but load time is excessive and they do not play smooth. The videos are simple MPG/MP4 files. This was not an issue before upgrading to Firefox 5

Hasan 477 solutions 5600 answers


Check and tell if its working.

Question owner

No...Now none of the 3 videos are displaying or playing again!