The FireFox 64 bit version 43.0.3 is not working with ANY Flash videos or streaming audio. This is a likely a serious broken code bug with the sandbox that cripples the 64 bit version for all practical purposes--it makes it unusable for anything that requires Flash. I have already submitted several crash reports when prompted. I am running Win7 64bit, SP1 all up to date. I uninstalled and deleted the folders for my 32 bit completely, then performed a fresh install and created a new profile from scratch to troubleshoot this. No script blocking or any other plugins that would block connections or sites were installed, and any remnant folders from FF 32bit were deleted. This is the consistent error generated: TypeError: Error #1009: Cannot access a property or method of a null object reference. at flash.external::ExternalInterface$/_callIn() at Function/<anonymous>() Troubleshooting Steps: In access:config type "plugins" (no quotes) dom.ipc.plugins.sandbox-level.default - for all plugins (default is 1 (for x64 FF), max 3, disabled - 0 (default for 32-bit FF)) dom.ipc.plugins.sandbox-level.flash - only for flash (default is 2 (for x64 FF), max 3, disabled - 0 (default for 32-bit FF)) Set both sandboxes to 1, and plays, but crashes when the stream is paused or stopped. Changed the plugin sandbox default to 0, the flash set to 0 (disabled) Went through all possible sandbox level combinations (closing and reopening browser to reset after each change) with no effect. Does not work with the Primetime CDM plugin Active or disabled and no other Flash installed. When installed, current Shockwave Flash plugin (version 20.x.x), set to Always, or Never Activate fails. Set Shockwave to ask every time and manually approving the request works initially, then generates the error and crashes during playback. Error message continues to pop up after closing. Test sites/files: www.slacker.com/station/song-of-the-year YouTube: Any video. Using plugin YouTube Flash-HTML5 set to HTML5 --works without issues. The Flash setting crashes or does not play at all. For the benefit of others aTemporary Workaround: If you have Internet Explorer 11 installed: Use the "Open in IE" extension with the current Adobe Flash ActiveX plugin--Verify that ActiveX filtering in IE is turned off. Everything plays normally. No crashes during playback or after closing a file. I cannot guarantee it will work if you also install script/ad blockers or things like Disconnect. But that leaves you open to intrusive ads, hijacking, and injected malware. After being fairly reliable up until version 41, I now regret permanently deleting my FireFox 32bit, but I did archive my old profile in case I want to reinstall the Win32 version clean again. FEBE is my friend. This 64 bit version is not yet ready for primetime. The FireFox team needs to address as their highest priority if they want to actually transition to HTML5 video/audio playback before most of the rest of the world has actually done it.