Use "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit) to close Firefox if you are currently doing that by clicking the close X on the Firefox title bar. In case you use "Clear history when Firefox closes" then try to disable this feature to see if that helps. *Tools > Options > Privacy > Firefox will: "Use custom settings for history": [] "Clear history when Firefox closes" Let all cookies expire when Firefox is closed to make them session cookies. *Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: Keep until: "I close Firefox" Create a cookie 'allow' exception for cookies that you would like to keep. *Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: Exceptions