Hello abohammam

1. In the Location bar, type about:config and press Enter. The about:config "This might void your warranty!" warning page may appear.
2. Click I'll be careful, I promise!, to continue to the about:config page.
3. In the Search field box at the top, type browser.tabs.warnOnCloseOtherTabs
4. Double-click on it to make it FALSE.

also, UNcheck the Warn me when closing multiple tabs, in Options > tabs

thank you

Does that happen when you use Firefox (or File) -> Exit to close Firefox?

I tried this and it doesn't work for me :(

I still have the same problem

When I close firefox It comes

See the picture

Hello, try to make FALSE the next : browser.warnOnQuit

and the next FALSE : browser.showQuitWarning (probably it is already False)

(always in about:config)

thank you

Thanks that was helpful