

The check box to ''warn you when quitting the browser'' in the Firefox General panel under Startup is for when "Restore previous session" is enabled, to warn you when closing Firefox with multiple tabs open. Read this answer in context 👍 0 All Replies (5) To close Firefox, I had to use the X at the top of the window or go to the Firefox 3-bar menu and click Exit. When I tried to close the last tab, Firefox opened the New Tab page. I tested in Firefox 77 on Windows 7 by setting this preference to false. You can try this solution, from In about:config, find the preference and set it to false. You should go to about:config and reset the preference back to true (the default setting) so you are warned when closing Firefox with multiple tabs open if you later disable the "Restore previous session" Startup option. The check box to warn you when quitting the browser in the Firefox General panel under Startup is for when "Restore previous session" is enabled, to warn you when closing Firefox with multiple tabs open. Firefox closes without warning by default, when you close the last tab.
