Always use TNEF formatting in S/MIME messages

Supported on: At least Windows Server 2008 R2 or Windows 7

Registry

HKCU software\policies\microsoft\office\16.0\outlook\security

Value name: forcetnef

Enabled: forcetnef = 1

Disabled: forcetnef = 0

Description

This policy setting allows you to specify the formatting when sending S/MIME messages. If you enable this policy setting, Outlook always uses TNEF formatting when sending S/MIME messages. If you disable or do not configure this policy setting, Outlook uses the format specified by the user when sending e-mail messages, including when sending S/MIME messages.