Interactive logon: Display user information when the session is locked This policy setting determines whether the account name of the last user to log on to the client computers in your organization can display in each computer's respective Windows logon screen. If you enable this policy setting, intruders cannot collect account names visually from the screens of desktop or laptop computers in your organization.

(1) GPO: Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options!Interactive logon: Display user information when the session is locked (2) REG: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System!DontDisplayLockedUserId