Hi Omer, it sounds like you are saying that you have this Startup setting on: "Open previous windows and tabs". When Firefox restores your session automatically, then the menu item for "Restore previous session" is either missing or grayed out. But you should find these: * menu button > History > Recently Closed Windows * (menu bar) History > Recently Closed Windows Do those list any missing windows? If you got nothing, it could be caused by Firefox not finding the session history files at startup. Some possible reasons for that are: (1) Firefox is set to clear browsing history when it closes (2) External cleaning software such as CCleaner or Advanced SystemCare removes one or more history-related files By the way, using the menu to close Firefox gives the cleanest restore. Either: * menu button > Exit * (menu bar) File > Exit