Disable "Require device sign in" Recent versions of Firefox have a new security setting that requires you to enter your system password to access your stored passwords, including during autofill. Open Firefox and go to the Settings menu. Click on Privacy & Security in the left-hand panel. Scroll down to the Logins and Passwords section. Look for the setting that says "Require device sign in to fill and manage passwords." Uncheck this box. After unchecking this, restart your browser and see if the issue is resolved. 2. Adjust the Password Timeout Setting You mentioned trying signon.masterPasswordReprompt.timeout_ms. While you had the right idea, this setting controls the timeout after you have already entered the primary password once. The value is in milliseconds. To set it to ask for the password once per session, the correct behavior is that the timeout value doesn't matter, as long as the first prompt is accepted. You can double-check its value by typing about:config into your address bar and searching for signon.masterPasswordReprompt.timeout_ms. The default value is 900000 (15 minutes). Setting it to 0 would mean it asks for the password every time it's needed, which is the opposite of the behavior you want.