How to Open winmail.dat Files on a Mac

Updated June 10th, 2019.

Sometimes you get an email with an attachment called “winmail.dat.” You’re never able to open it– unless you use Josh Jacobs’ excellent “TNEF’s Enough” program. It’s available on the Mac App Store for free via this link.

Easiest way to use it: put TNEF’s Enough into your Dock, then drag winmail.dat files from your email program to the TNEF’s Enough icon. The rest you’ll figure out.

TNEF’s Enough allows Macs to read and extract files from Microsoft TNEF stream files. The files are usually received by SMTP based e-mail programs from Microsoft Exchange and Microsoft Outlook users. The SMTP based e-mail program will usually receive either a MIME attachment named “winmail.dat” or a MIME attachment with the type “application/ms-tnef.”

The file is a rich text (or MAPI) message that is sent from Outlook to Exchange. When Exchange sends the message to an outside server it writes the MAPI message as a MIME attachment. The unfortunate side effect of this plan is if the Outlook user has someone in their address book as a person who can receive “Rich Text” then the user will receive the TNEF file whether the user uses Outlook or not.

The app is free, but you can donate to the developer if you’d like to, and considering how much trouble TNEF’s Enough saves us, I think we all should do it. See this web page for more information.


Did this article help you?

Maybe you'd like to contribute to the
Christian Boyce coffee fund.




Want some some quick iPhone how-tos?
Visit me at iPhoneinaminute.com.

Looking for in-depth tutorials?
See my christianboyce.com website!



Please use the “Sharing” buttons to share what’s interesting with your friends. It helps them and it helps the blog. Thank you very much!

Sincerely,
Christian signature
Christian Boyce

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Proudly powered by WordPress | Theme: Baskerville 2 by Anders Noren.

Up ↑

Read our Privacy Policy