Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems

This article is no longer maintained, so its content might be out of date.

Support ended for all NPAPI plugins, except for Adobe Flash, in Firefox version 52. See this article for details.

If you are having problems with pages that use plugins (such as Adobe Flash, Java and others) to display content, you may need to check to see whether a plugin is causing the problem.

Note: The 64-bit version of Firefox recognizes and supports only the Adobe Flash and Microsoft Silverlight NPAPI plugins.

Common problems caused by plugins include:

This article describes how to troubleshoot plugins. If you are having a problem with an extension or theme, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems. For general information on plugins, see Use plugins to play audio, video, games and more.

Determining if a plugin is the problem

You can selectively disable plugins while Firefox is running. If you suspect a certain plugin, disable it first, then test for your problem. If you don't know which plugin to disable:

  1. Click the menu button Fx89menuButton, click Add-ons and themes and select Plugins.
  2. Select a plugin in the list and then select Never Activate in its drop-down menu. Repeat this step for each plugin in the list, until all of them are disabled. You do not need to restart Firefox for the changes to take effect.
  3. Test for your problem. If it does not occur, go back to the Add-ons Manager tab and re-enable plugins one-by-one with the Always Activate drop-down menu until you find which one causes your problem to occur.

If you find that disabling a plugin fixes your problem, continue following the steps in this article.

Updating or re-installing your plugins

Many problems with plugins can be solved by updating to the latest version of the plugin.

If updating to the newest version of the plugin or reinstalling it does not fix the problem, you can leave it disabled.

Manually uninstalling a plugin

If you can't use an uninstaller program to remove a plugin, you can remove it manually:

  1. Type about:plugins into the address bar and press EnterReturn to display the About Plugins page.
  2. Each entry in the About Plugins page will have "File:" and "Path:", showing the name and location of the plugin file. Use Windows Explorer to navigateNavigate to the folder shown for the plugin you want to remove.
  3. Rename the file to add an X in front of the filename (for instance, npswf32 becomes Xnpswf32).

The plugin will be removed.

Re-initializing the plugins database

In some cases, you may not be able to install or re-install a plugin. Re-initializing the plugins database may fix this problem:

  1. Open your profile folder:

    • Click the menu button Fx89menuButton, click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
    • Under the Application Basics section next to Profile FolderDirectory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

  2. Click the Firefox menu Fx89menuButton and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx89menuButton and select Quit.
  3. Delete the pluginreg.dat file.
  4. Open Firefox
  5. In the Location bar type about:plugins and press EnterReturn to bring up the Firefox plugins list.

These fine people helped write this article:

Illustration of hands


Grow and share your expertise with others. Answer questions and improve our knowledge base.

Learn More