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To download Winmail.dat Viewer - Letter Opener 9 from the Mac App Store, you need a Mac with OS X 10.6.6 or later. Learn More.

Winmail.dat Viewer - Letter Opener 9

By Atlan Creative GmbH

Open the Mac App Store to buy and download apps.


Open Winmail.dat, MSG and XPS files with just a double-click.

Try all in-app purchases 14 days for free!

A winmail.dat file is an email from Microsoft Outlook that can not be read by other email applications. It needs to be converted for the content to be accessible.

Letter Opener does that with a simple double-click!

With 10 years experience (and a special dislike for winmail.dat files) we made sure that working together with Microsoft Outlook and Windows users can be simple and seamless.

- Open winmail.dat and MSG files and convert Microsoft Outlook appointments, notes, contacts etc. to macOS native formats.

- Convert Microsoft XPS documents to Adobe PDF files

- Quickly view the contents of a Winmail.dat, MSG and XPS file with a tap on your space-bar via Quick Look

- Once extracted, files can be treated like any other file on your computer

Letter Opener speaks your language! It’s fully localized in Arabic, Chinese, Dutch, French, German, Hindi, Italian, Japanese, Korean, Portuguese, Russian, Spanish and Swedish.

- Winmail.dat Premium: Access to attachments in winmail.dat files
- MSG Premium: Access to attachments in MSG files
- XPS Premium: Convert XPS files to PDF files
- File Extension Premium: Fix files with the wrong or no extension

The trial allows you to use all premium-features 14 days for free! After the trial period you can keep reading message text. The premium add-ons can conveniently be purchased individually.

We provide direct personal support, so don’t hesitate to contact us if you have any questions or comments:

Thanks for helping us to keep improving Letter Opener!

What's New in Version 9.2.1

- Improvements
- Added localizations
- Bug fixes

If you encounter any problems or have questions please go to Help > Feedback Assistant to send a report or contact us via email:

Please consider writing a short review or to rate Letter Opener. Thank you!


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Customer Reviews

works great for me

i have a Mac I and I couldn’t open any windat files.. Yes, I had to pay the fee to get the full version, but its worth every penny and it wasn’t that spendy. My only beef is that I cant open on my iPhone unless i go through a few screens. Its awesome the ipad version works good too..

Huge Help!

This application has been such a huge help for me. I have certain business contacts whose email always corupts their attachments. This application works perfectly every time, and has saved me a lot of back and forth with these contacts.

Works Great!

i have a Mac I and I couldn’t open any windat files which I now get a lot of. I would have to go find my iPad and look at them that way; but, now with this program they open quickly and easily. Well worth the investment!

Winmail.dat Viewer - Letter Opener 9
View in Mac App Store
  • Free
  • Category: Productivity
  • Updated:
  • Version: 9.2.1
  • Size: 12.4 MB
  • Languages: English, Arabic, Dutch, French, German, Hindi, Italian, Japanese, Korean, Portuguese, Russian, Simplified Chinese, Spanish, Swedish
  • Seller:

Compatibility: OS X 10.9 or later, 64-bit processor

Customer Ratings

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Top In-App Purchases

  1. Winmail.dat Premium$9.99
  2. MSG Premium$9.99
  3. XPS Premium$9.99
  4. File Extension Premium$4.99