Click the Firefox menu at the top of the screen and select Quit Firefox.

Click the Firefox menu and select Exit.

Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox. To resolve hanging problems not specifically mentioned in this article, or if the suggested solutions do not solve the problem, see Troubleshoot and diagnose Firefox problems.

If Firefox closes unexpectedly, see Troubleshoot Firefox crashes (closing or quitting unexpectedly).

If you get a 'Warning: Unresponsive script' prompt, see Warning Unresponsive script - What it means and how to fix it.

If Firefox uses a lot of computer resources, see the solutions proposed in Firefox uses too much memory or CPU resources - How to fix.

This article gives you solutions to Firefox hangs depending on when they happen.

Also, the mouse becomes a spinning wait cursor when it's over the Firefox window. Also, a '(Not Responding)' label is displayed in the title bar and the mouse cursor becomes a spinning wheel when it's over the Firefox window. When Firefox hangs, it stops responding to your clicks and keystrokes and doesn't seem to be doing anything. Firefox hangs or is not responding - How to fix

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