At startup, Firefox reads the "Policy" keys in the Windows registry, and a policy can at least partially block use of the Password Manager. Here are some links to get you started down that road: [[Customizing Firefox Using Group Policy (Windows)]] (these end up in the Registry) https://github.com/mozilla/policy-templates#offertosavelogins That probably doesn't prevent manually saving logins. You could look at whether any other policies cover that.