Firefox usually forgets a website sign-in because the site’s login cookie was removed or not retained. Check whether Firefox clears cookies, site data, or history when it closes; then check private browsing, the affected site’s stored data, and extensions or cleanup software. The right starting point depends on whether this happens on one site or many, and whether it happens while Firefox is open or only after you quit.
Why does Firefox keep logging me out of websites?
Websites can use cookies to remember that you are signed in. If Firefox or another utility deletes the relevant cookie, the site may no longer recognize your session and will ask you to log in again. Mozilla explains how cookies can store login status and how Firefox handles them in its cookie guide.
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There is no single confirmed cause for every repeated sign-out. The pattern is useful: one affected site points toward that site’s data or behavior, while several affected sites—especially after quitting Firefox—make browser-wide retention settings or cleanup software worth checking first.
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- One site or many? If only one site forgets you, start by checking that site’s stored data. If many sites do, review Firefox-wide settings and software that can remove browser data.
- While Firefox stays open or after it closes? If the sign-in disappears only after you quit and reopen Firefox, check close-time history and cookie settings. If it happens during an open session, inspect the affected site’s data and consider extensions or other software.
These are practical ways to narrow the problem, not a formal Mozilla diagnostic checklist.
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Check Firefox’s cookie, site-data, and history settings
Open Firefox’s Settings, select Privacy & Security, and review the Cookies and Site Data controls. Mozilla’s instructions for clearing cookies and site data describe the available controls and how to manage data for particular sites. Labels and layout may vary by Firefox version and operating system.
Look for a setting that removes cookies or site data when Firefox closes. Also review the history controls for an option to clear history on close: community replies on Mozilla Support identify this and private browsing as possible explanations for sign-ins that do not persist, but these are suggestions to check rather than a definitive diagnosis. If you use a custom history setting, verify that it is not configured to discard cookies or site data when Firefox closes.
If you are browsing in a private window, do not assume that a sign-in will be retained like it is in a regular session. Test the site in a normal Firefox window before changing other settings.
If just one website forgets you, inspect that site’s data
Firefox lets you find and manage stored data for individual websites. In Settings > Privacy & Security > Cookies and Site Data, use the site-data management control to locate the affected site; consult Mozilla’s site-data instructions if the control is labelled differently in your version.
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Removing that site’s cookies and data can be a useful diagnostic step if its stored information is stale or causing trouble. It also deletes remembered sign-in state and may remove site preferences, so expect to sign in again after clearing it. Avoid clearing all browser data as a first step when only one site is affected.
Test extensions and other cleanup software
If Firefox’s retention settings look right, check whether an extension or another program is removing cookies. Cookie-control add-ons, privacy tools, and external cleanup or security utilities may be configured to delete browser data. Review their settings and disable only a suspected tool temporarily so you can see whether the sign-in persists.
Mozilla recommends Firefox Troubleshoot Mode as a way to investigate problems that may involve extensions, themes, or hardware acceleration. Follow the current Troubleshoot Mode instructions. If the sign-out problem does not happen in that mode, investigate those Firefox components; Mozilla also notes that extensions or internet-security software can affect site behavior.
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- Sign in to the affected site in a regular Firefox window.
- Wait or browse long enough to see whether the sign-in disappears while Firefox remains open.
- If the problem normally occurs after quitting, close and reopen Firefox, then revisit the site.
- If the sign-in is lost, change one setting or disable one suspected extension or utility, then repeat the same test.
Changing one thing at a time makes it easier to identify the cause and undo an ineffective change. If a site still signs you out after Firefox retains its cookies and the issue also occurs without extensions, the site itself may be ending the session; check its account or session settings or contact the site’s support.
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