Hi Naddy, when you close a window, Firefox adds it to the "Recently Closed Windows" list on the History menu. When you restore the session, up to 3 windows will appear on that list. I think there is a difference between Mac and Windows, because when you close the last window in Windows, Firefox exits automatically without the "you are closing a bunch of tabs" warning. On Mac, Firefox may be able to keep running without any visible windows, so it may show that warning. Or is it a different warning? Anyway, you are definitely correct that using Quit is the best way to use Restore Previous Session because then you don't have to use the Recently Closed Windows list to re-open windows you had open at quit time.