Winmail Viewer - Letter Opener 4+

Open Email, MSG & XPS files

Letter Opener GmbH

    • 4.6 • 1.9K Ratings
    • Free
    • Offers In-App Purchases


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 15.0.1

Improved Winmail.dat, MSG and XPS file support.

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

Ratings and Reviews

4.6 out of 5
1.9K Ratings

1.9K 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.


Works for me!

I just converted to a Mac after a decade of having to use a PC at work. With that, I have hundreds upon hundreds of emails saved in .msg format. Since Outlook for Mac doesn't open .msg I had to find a tool. After trying a dozen or so, this one definately works the best. It's simple to ease and pretty cheap for what it does!

Obbie P ,

Mac mail integration doesn't work

I have Sonomo 14.1.1 installed and it doesn't integrate. I paid for the pro license for the integration. There is a msg suggested saying integration is coming but i suspect this msg has been present for a long time. The product works great other than the false adverstising inducing me to pay for the Pro version which has no benefit. I sent a letter to support but no one responded. It would be a 5 if the integration worked.

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

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