Mac: received attachments appear as winmail.dat
Software: Office 2011 & 2016 | Last modified on 2018-06-18
All received attachments within emails appear as winmail.dat files. This happens when the sending app uses the Transport Neutral Encapsulation Format (TNEF).
[Solution 1] Send emails as plain text
This step only applies as the sender of the attachments.
- Open the Outlook app.
- Open File and click Options
- Click Mail and change Compose messages in this format to Plain Text.
- Restart the Outlook app and resend the attachment.
[Solution 2] Install the Winmail.dat Viewer
This step only applies as the recipient of the attachments.
- Open the App Store and install Winmail.dat Viewer.
- Open the Outlook app and save the Winmail.dat file in your downloads folder.
- Open the Winmail.dat Viewer app and use it to open the saved attachment.