
(3) Disable protected mode (Windows Vista and higher) More information in this support article from Adobe: (B) In Flash, right-click the media and choose Settings, then the first mini-tab and uncheck the box to use hardware acceleration. That takes effect the next time you exit and start Firefox up again. "3-bar" menu button (or Tools menu) > Options > Advanced > General > "Use hardware acceleration when available" (2) Disable hardware acceleration in Firefox and in Flash (1) If you have any recorders/downloaders that interact with Flash media make sure they are as up-to-date as possible, or disable them temporarily. It might partially duplicate the above, but just in case:

This is some standard guidance that addresses the most common issues with the Flash Player plugin.

ActiveX is for IE and possibly for some desktop applications that embed Flash.
