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 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 if he/she wishes.

Letting Firefox wait more seconds for a hung plugin

If you want Firefox to run longer before a hung plugin, you can specify the amount of time it should wait for a hung. As an example, if you find that pressing the Continue button brings up the same dialog again, letting Firefox run longer won't help you; it will just make Firefox hang again. However, if you can use Firefox normally after pressing Continue, then the plugin may just needs extra time to complete.

To tell Firefox to wait more for the plugin hung:

1. In the Location bar, type about:config and press Enter. The about:config "This might void your warranty!" warning page may appear. Click "I'll be careful, I promise!", to continue to the about:config page.
2. In the about:config page, search for the preference dom.ipc.plugins.hangUITimeoutSecs, and double-click on it.
3. In the Enter integer value prompt, type a value for the number of seconds Firefox waits for a hung plugin before displaying the Plugin Hang UI.

Waiting longer for hung plugin, you may no longer receive the prompt. If you still receive the prompt (or if you want to see it again), you should set that preference back to the default value.

1. In the Location bar, type about:config and press Enter.
2. The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise!, to continue to the about:config page.
3. In the about:config page, search for the preference dom.ipc.plugins.hangUITimeoutSecs.
4. Right-click on it and choose Reset.

Change the amount of time the Hang UI is displayed

You can change the amount of time Firefox lets the Hang UI being displayed before terminating the plugin automatically, even if the user did not elect to stop the plugin using the Hang UI. To change the amount of time Hang UI is displayed, set the value of preference dom.ipc.plugins.timeoutSecs.

1. In the Location bar, type about:config and press Enter. The about:config "This might void your warranty!" warning page may appear. Click "I'll be careful, I promise!", to continue to the about:config page.
2. In the about:config page, search for the preference dom.ipc.plugins.timeoutSecs, and double-click on it.
3. In the Enter integer value prompt, type a value for the number of seconds Firefox waits for a hung plugin before displaying the Plugin Hang UI.

Minimum time that Hang UI is displayed

You can also set the minimum number of seconds that Firefox should display the Plugin Hang UI. To change the minimum number of seconds that Plugin Hang UI is displayed you should change the value of preference dom.ipc.plugins.hangUIMinDisplaySecs

1. In the Location bar, type about:config and press Enter. The about:config "This might void your warranty!" warning page may appear. Click "I'll be careful, I promise!", to continue to the about:config page.
2. In the about:config page, search for the preference dom.ipc.plugins.hangUIMinDisplaySecs, and double-click on it.
3. In the Enter integer value prompt, type a value for the number of seconds Firefox waits for a hung plugin before displaying the Plugin Hang UI.