= Outlook: How to stop sending winmail.dat attachments =

== Problem ==

When sending an email signed with an S/MIME certificate, it can arrive with a winmail.dat attachment on non-Outlook clients. This file includes the email, the S/MIME signature, and any other attachments, making it cumbersome for recipients like support@isg.ee.ethz.ch to extract the contents. To prevent this, you can enable the "Send clear text signed message when sending signed messages" setting in Classic Outlook.

== Solution ==

{{{{#!wiki important
This setting must be enabled '''before''' creating an email, as it is not applied to the current email being edited.
}}}}

1. '''Open Options Window'''

 * Go to the '''File''' menu in the top-left corner of the main page.

{{attachment:winmail_dat_file_menu.png}}

 * Click on '''Options''' at the bottom-left corner.

{{attachment:winmail_dat_options.png}}

2. '''Access Trust Center Settings'''

 * Click on '''Trust Center''' in the left menu.

 * Open it by clicking the '''Trust Center Settings''' button.

{{attachment:winmail_dat_trust_center.png}}

3. '''Enable Clear Text Signed Messages'''

 * In the Trust Center, select '''Email Security''' from the left menu.
 * Enable '''Send clear text signed message when sending signed messages''' to avoid sending winmail.dat attachments.

{{attachment:winmail_dat_clear.png}}

By following these steps, you can ensure your emails arrive without the winmail.dat attachment, making it easier for recipients to access your email and attachments.
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[[CategoryWNSU]]