Firefox crashes when viewing Youtube videos

This article is no longer maintained, so its content might be out of date.

The template "crashsig" does not exist or has no approved revision. NPSWF32.dll

If Firefox is crashing when you try to view videos on YouTube, it is usually caused by the Flash plugin conflicting with one of your extensions.

Note: This article applies to the Windows version of Firefox only. For Flash related crashes on Mac OSX, see Pages that use the Flash plugin crash on Mac.

Update Firefox

Firefox 3.6.4 and above load plugins separately from Firefox, allowing Firefox to stay open if a plugin crashes. To make sure you are using the latest version of Firefox, see Update Firefox to the latest release.

Conflict with extensions

Firefox extensions can cause this crash. To test whether your crash is happening because of an extension, try launching Firefox's Troubleshoot Firefox issues using Safe Mode: Click the menu button New Fx Menu , click help Help-29 Click the menu button Fx57menu , click Help and select Restart with Add-ons Disabled…. Firefox will start up with the Firefox Safe Mode dialog.

Note: You can also start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.quitting Firefox and then going to your Terminal and running: firefox -safe-mode
You may need to specify the Firefox installation path (e.g. /usr/lib/firefox)

  1. In the Firefox Safe Mode dialog, click Continue in Safe Mode.
  2. Attempt to view videos to test for the crash.

Flash plugin

The NPSWF32.dll file is associated with the Flash plugin. If the crash still happened in Firefox's safe mode, try uninstalling and re-installing the Flash plugin:

  1. For instructions on uninstalling the Flash plugin, see's article on uninstalling Flash.
  2. To re-install Flash, go to the Adobe Flash Player download page.
  3. Click the Download now button to download the installer.
  4. After you've downloaded the installer file, double-click it and then follow the on-screen instructions.
  5. Restart Firefox.
// These fine people helped write this article:Thomas, Tonnes. You can help too - find out how.
Volunteer for Mozilla Support