Details like websites remembering you (log you in automatically) are stored in a cookie. *Create a cookie 'allow' exception to keep such 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 Clear the cache and cookies only from websites that cause problems. "Clear the Cache": *Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now" "Remove Cookies" from sites causing problems: *Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies" If clearing cookies didn't help then it is possible that the cookies.sqlite file that stores the cookies got corrupted. *Rename (or delete) <b>cookies.sqlite</b> (cookies.sqlite.old) and delete other present cookies files like <b>cookies.sqlite-journal</b> in the Firefox profile folder in case the file cookies.sqlite got corrupted. *https://support.mozilla.org/kb/Cookies *https://support.mozilla.org/kb/Deleting+cookies

选项里的隐私设置都没用，删除了cookies.sqlite和其他几个cookies文件才解决