An issue with Gmail persistently logging out in Firefox can affect productivity and have a negative impact on internal and external communications, so it should be addressed as soon as possible. The root cause of the problem may lie with Firefox's built-in Password Manager tool, a faulty extension running on top of the browser, blocked cookies, or interfering security software. If troubleshooting doesn't identify the problem, you can reset or reinstall Firefox.
Firefox comes with a built-in Password Manager tool for remembering usernames and passwords for services such as Gmail, accessed from the Security tab of the Options dialog. Ensure the "Remember passwords for sites" box is checked, and click "Exceptions" to make sure Gmail isn't listed. Log in to Gmail normally, checking the "Stay signed in" box on the login screen, and then select "Saved Passwords" from the Options dialog to verify the Gmail information has been retained. In addition, open the "Privacy" tab, and if a custom settings profile is configured click "Settings" and ensure the Saved Passwords box isn't checked.
Video of the Day
Cookies are small pieces of code stored on your computer to remember your location and password settings for certain sites. On the Privacy tab of the Firefox options dialog, select the "Remember history" option from the History drop-down menu. If a custom configuration is active, ensure the "Accept cookies from sites" box is checked and that Gmail isn't listed as an exception. In addition, don't use the Private Browsing mode when visiting Gmail (indicated by a purple Firefox menu), as this overrides the default cookie settings. Select "Stop Private Browsing" from the Firefox menu to return to the normal browsing mode.
It's possible that a third-party security program, such as a firewall or anti-virus tool, is interfering with the password storing process. Open your installed security software and check for restrictions placed on Firefox and Gmail. Ensure that both the browser and the website are allowed to operate freely. The exact procedure and nature of the settings screen varies from program to program, but check the program's help documentation for pointers. In addition, check for Firefox extensions related to security or privacy that may be preventing cookies from being stored or clearing username and password information on a regular basis.
Reset and Reinstall
Firefox includes a number of built-in reset tools that may clear up the Gmail problem. Click "Firefox," "History" then "Clear Recent History" to wipe cookie and cache information from the browser, choosing "Everything" from the drop-down menu. This process removes cookies and temporary files that may have become damaged or corrupted. A more general reset option is available from the Troubleshooting Information section of the Help menu that restores Firefox's defaults and can resolve a wide range of problems. If the Gmail issue persists, uninstall Firefox from Control Panel and download and install the latest version of Firefox from the Mozilla website. This process resets all of the browser's files and settings, replaces any files that may have been deleted or modified, and applies the latest bug fixes and updates from the Firefox developers.