Simplest way is to start by uninstalling and reinstalling the latest Firefox and Flash player

You can check for problems with current Shockwave Flash plugin versions and hardware acceleration in Firefox and try this:

• make sure you have the latest Flash version:
  http://www.adobe.com/special/products/flashplayer/fp_distribution3.html
• check for updates for your graphics drive drivers
  https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration
• disable protected mode in the Flash plugin (Windows Vista and later)
  https://support.mozilla.org/kb/adobe-flash-protected-mode-firefox
• disable hardware acceleration in the Flash plugin
  https://helpx.adobe.com/flash-player/kb/video-playback-issues.html
• disable hardware acceleration in Firefox
  https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

See also:

• http://kb.mozillazine.org/Flash#Troubleshooting

No go 1) There is no protected mode options button shown in Nightly for Flash plugin 2) I do have the latest version of Flash and Nightly 3) I have the latest version of nVidia drivers installed 4) I disabled all Hardware acceleration in Firefox and Flash still the same effect 5 I used the uninstaller from for Flash, removed flash downloaded the network installer of flash for firefox. After reinstallation flash worked once then once firefox is shut down it will no longer work. That is the same effect I received when I used the refresh firefox button in the troubleshooting menu. I did also uninstall and reinstall Nightly. I still have this in Windows 7 and Windows 10 on two different machines.

Any other ideas to try? I personally think something has changed in firefox.

Mike

I seem to have solved the problem for now. Thank you for all your help. I agree that something has changed in Firefox.

Extended Support Release - Flash Player 18.0.0.333 was the answer to my problem. No more Context3d Errors

Glad you are back online