Crash signatures ^{( what's this? )}: 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.

• For troubleshooting other crashes, see Firefox crashes.

Table Of Contents

• Conflict with extensions
• Flash plugin

Conflict with extensions

Firefox extensions can cause this crash. To test whether your crash is happening because of an extension, try launching Firefox's Safe Mode:

1. Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Exit menu item.Close down Firefox completely: On the menu bar, click the Firefox menu, and select the Quit Firefox menu item.Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Quit menu item.
2. In Windows, click Start, open the All Programs list, and navigate to the Mozilla Firefox folder. In the Mozilla Firefox folder, select Mozilla Firefox (Safe Mode).Hold down the Option key, as you start Firefox.Go to your Terminal and run:

   firefox -safe-mode

   You may need to specify the Firefox installation path (e.g. /usr/lib/firefox-3.5).
3. Firefox should start up with a Firefox Safe Mode dialog.
   
   Note: You can also start Firefox in Safe Mode by clicking Start, selecting Run (or use the Start Search box in Windows 7 and Vista) and then entering the following in the text field:
   

   "%PROGRAMFILES%\Mozilla Firefox\firefox.exe" -safe-mode

4. In the Firefox Safe Mode dialog, click Continue in Safe Mode.
5. Attempt to view videos to test for the crash.
   • If the problem does not occur in Safe Mode, an extension is likely the cause. To narrow down which extension is causing problems, see Troubleshooting extensions and themes.
   • If the problem still occurs in Safe Mode, follow the instructions in the next section of this article.

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 Adobe.com's article on uninstalling Flash.
2. To re-install Flash, go to the Adobe Flash Player download page.
3. Click the Agree and install 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.