If you haven't already, try disabling the new protected mode in Flash 11.3, since that feature is currently being debugged. See this support article from Adobe under the heading "Last Resort": [http://forums.adobe.com/message/4468493 Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?] Firefox support articles on Flash 11.3: * [[Flash 11.3 crashes]] * [[Flash 11.3 doesn't load video in Firefox]] Flash 11.4 beta 2 download page if you want to try it: [http://labs.adobe.com/technologies/flashplatformruntimes/flashplayer11-4/ Adobe Flash Player 11.4 Beta for Desktops - Adobe Labs] (I haven't tried it myself)