Websites remembering you and automatically log you in is stored in a cookie. * Create an allow cookie exception (Tools > Options > Privacy > Cookies: Exceptions) to keep such a cookie, especially for secure websites and if cookies expire when Firefox is closed. * In [[Private Browsing]] mode all cookies are session cookies that expire if that session is ended, so websites won't remember you. * In [[Private Browsing]] mode Firefox won't fill names and passwords automatically and won't offer to store new passwords. * Do not use [[Clear Recent History]] to clear the "Cookies" and the "Site Preferences" Clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, and passwords. * http://kb.mozillazine.org/Cookies