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

Open one file per week 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.

Open unlimited files of all supported file types with the Letter Opener Subscription.

- 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

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 14.1.0

Letter Opener 14 comes with a shiny new app icon, matching the style of your Dock on macOS Big Sur and Monterey. We also refreshed the main window to make using it more a more joyful experience.

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

Ratings and Reviews

3.7 out of 5
718 Ratings

718 Ratings

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

kristen 999999 ,

works great

this application works great. i often get attachments from PC users in that dat format I can’t open/read on my mac - this solves that problem like a charm. it was easy and fast to install. also you aren’t taken to another screen to open attachments; it’s seamless—you just click on it and it opens.

App Privacy

The developer, Letter Opener GmbH, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Identifiers
  • Usage Data
  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

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

More By This Developer

You Might Also Like