Open winmail.dat files

Automatically in macOS Mail

See how it works – Replay

Letter Opener for macOS Mail Icon

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Requires macOS Sierra or El Capitan or Yosemite
Release Notes

Maximize your productivity

Never think about winmail.dat attachments again.

What’s in a Winmail.dat file?

An email message from Microsoft Outlook.

Letter Opener speaks your language.

Fully localized in Arabic, Cat, Chinese, Dutch, French, German, Hindi, Italian, Japanese, Korean, Portuguese, Russian, Spanish and Swedish.


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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Letter Opener for macOS

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

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Letter Opener for iOS

Get full-featured winmail.dat viewing power for iPhone & iPad that doesn’t feel like you left something important back at the office.

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