Letter Opener for macOS Mail

Automatically converts winmail.dat files

Available for macOS Sierra
Sierra ready version for Letter Opener for macOS Mail is available.

Get Letter Opener for macOS Mail — Try it 14-days for free

Letter Opener converts seamlessly winmail.dat file inside macOS Mail. The most popular mail application on macOS.

Letter Opener for macOS Mail

Try it 14-days for free.

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We think you’ll love our apps - and provide email support directly from the people who build our apps to help you whenever you need it.

Available from our Store for $39.99.
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macOS Sierra 10.12, El Capitan 10.11 or Yosemite 10.10. . Click here to view the release notes.


macOS Version 9 Version 8 Version 7 Version 6 Version 5 Version 4
10.12 Sierra Intel
10.11 El Capitan Intel Intel
10.10 Yosemite Intel Intel Intel
10.9 Mavericks Intel Intel
10.8 Mountain Lion Intel Intel
10.7 Lion Intel Intel Intel
10.6 Snow Leopard Intel Intel Intel
10.5 Leopard Intel


There’s no fuss with Letter Opener, no need to drag the winmail.dat file onto another application or call upon several programs to help you. Once Letter Opener is installed, you can forget about it.

Outlook compresses all of its attachments together into one winmail.dat file, leaving the rest of us scratching our heads as to what's inside. With Letter Opener the attachments appear like any others!

What a relief! This solves a recurring problem, that was a major irritation! It works flawlessly and seamlessly. You never even know it's there!

Ted O.

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