Clear the Cache and remove the Cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences). "Clear the Cache": *Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now" "Remove the Cookies" from websites that cause problems. *Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies" ---- A detail like a website remembering you (log you in automatically) is stored in a cookie. You can use these steps to make a website recognize and remember you: *You can create a cookie" "Allow" exception to keep specific cookies, especially in case of secure websites and when cookies expire when Firefox is closed. *Tools > Options > Privacy > "Use custom settings for history" > Cookies: Exceptions If you remove the Cookies from a website then that makes the website forget about you. ---- In case you use "Clear history when Firefox closes" or otherwise clear history. *do not clear the Cookies *do not clear the Site Preferences *Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings *https://support.mozilla.org/kb/remove-recent-browsing-search-and-download-history *clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exception for password and other website specific data *clearing cookies will remove all selected cookies including cookies with an Allow exception you may want to keep If clearing cookies didn't help then it is possible that the cookies.sqlite file in the profile folder that stores the cookies got corrupted. *Rename/remove <b>cookies.sqlite</b> (cookies.sqlite.old) and if present delete cookies.sqlite-shm and cookies.sqlite-wal in the Firefox profile folder in case cookies.sqlite got corrupted. *http://kb.mozillazine.org/Profile_folder_-_Firefox