Warning Unresponsive plugin - What it means and how to fix it

Revision Information
  • Revision id: 42481
  • Created:
  • Creator: scoobidiver
  • Comment: plugin hang UI is not OOP, better intro, new headings with fixes and reverting
  • Reviewed: No
  • Ready for localization: No
Revision Source
Revision Content
Note: This article does not apply to Mac.
Note: This article does not apply to Linux.

Note: This applies to the latest Firefox release version which can be downloaded from mozilla.org/firefox.

Firefox may give you a "Warning: Unresponsive plugin" prompt that says "A certain plugin may be busy, or it may have stopped responding. You can stop the plugin now, or you can continue to see if the plugin will complete". This article describes the reasons for this error message and covers possible solutions and workarounds.

Firefox Plugin Hang UI

What to do

This error is telling you that Firefox thinks that a plugin may be running out of control and would make Firefox hang if nothing is done. The purpose of the Plugin Hang UI is twofold:

  • To inform the user which plugin is responsible for the hang and
  • Provide the user with an opportunity to terminate the plugin sooner than the default behavior.

When the Plugin Hang UI appears, you have some options, as you can see above.

Select to Continue

If you think that a plugin will finally complete, then you can select Continue. This way, you give a plugin more time to complete, although this may not always be succesful. Since the Plugin Hang UI has appeared, Firefox has suspended the plugin's execution. By selecting Continue you let the plugin resume execution, and so it may finally complete.

Select to Stop the plugin

If you find that pressing Continue brings up the same dialog again, then probably you should stop the plugin. You can do this by selecting Stop plugin.

Prevent plugins from hanging

If you see that prompt often, you may have:

  • oudated plugins.
  • several instance of the plugin running at the same time. Try to pause or stop the plugin in other tabs.

For Flash, see also Playing Flash videos makes Firefox hang

Disable the Plugin Hang UI

If you don't want to be warned when a plugin hangs, then you can disable this feature. If you check "Don't ask me again", then Firefox will not show this warning again and will behave as in earlier versions, that is it hangs and makes the plugin crash after 45 seconds.

If you want to see it again after disabling it, do the following:

  1. Type about:config in the address bar and press EnterReturn.
    A warning page may appear. Click Accept the Risk and Continue to go to the about:config page.
  2. In the about:config page, search for the preference dom.ipc.plugins.hangUITimeoutSecs.
  3. Right-clickHold down the Ctrl key while you click on it and choose Reset.