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

Version 9.2.2

• Bug fixes and improvements.

If you like Letter Opener, please consider leaving a review. That helps us a lot. Thanks!

Ratings and Reviews

3.6 out of 5
643 Ratings

643 Ratings

Don$108 ,

Pay the $20 and Get Over It

At least it works. And at least they tell you upfront that they charge for the app. Don’t bother with the mini versions, just pay the $20 and be done with it so that you can acturally view and save those annoying PC mail attachment things.

Developer Response ,

Hey Don, thanks for the review! The" mini versions" – or in-app purchases – you are talking about are fully capable of opening up winmail.dat files too! The 19.99 version of Letter Opener is an add-on for Apples "Mail" and opens winmail.dat files directly within "Mail", so there's a difference in functionality. For questions or more info about the differences and pricing, we are always here to help:

Tom1964 ,

Works Perfectly

The thing I want in a program like this is that it just plain ol' works without me thinking about it. This program solves the problem I've had of PC users sending me attachments as dat files that I couldn't open on my Mac. Now I can. The developer even proactively reached out to me to see if I was having any issues. Pretty great customer service, I'd say.

The Great C ,

Letter Opener Gets My Vote

Letter Opener Gets My Vote for being a great program. I have used it almost every day for the past 3 years and have not had any problems. I receive pdf & other files all day long from window users & have never had a problem opening the files. I highly recommend it!

John from Houston, Texas


Letter Opener GmbH
12.4 MB

OS X 10.9 or later, 64-bit processor


English, Arabic, Dutch, French, German, Hindi, Italian, Japanese, Korean, Portuguese, Russian, Simplified Chinese, Spanish, Swedish

Age Rating
In-App Purchases
  1. Winmail.dat Premium $9.99
  2. MSG Premium $9.99
  3. XPS Premium $9.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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