The Turn off Windows Mail application machine setting should be configured correctly. Denies or allows access to the Windows Mail application. If you enable this setting, access to the Windows Mail application is denied. If you disable or do not configure this setting, access to the Windows Mail application is allowed. Fix: (1) GPO: Computer Configuration\Administrative Templates\Windows Components\Windows Mail\Turn off Windows Mail application (2) KEY: HKLM\SOFTWARE\Policies\Microsoft\Windows Mail\ManualLaunchAllowed