2020 Update: 4 Best Winmail.dat Opener for Mac

Jose Henline
time April 08, 2020 Preview 15.8K
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“I sometimes receive email messages with a ‘winmail.dat’ file attached that I cannot open. I am a newbie to Mac, can somebody recommend me some document reader to open or view winmail.dat for Mac?”
“What is a winmail. dat file and should I look for a winmail viewer to open and view it?”

Know nothing about Winmail.dat files or want to find the best app for opening Winmail.dat file on mac? Here you will find all the answers.

Basics: What is Winmail.dat File?

When composing emails in Microsoft Outlook, Rich Text Format is applied to maintain the formatting. However, if the email recipient is not using Microsoft Outlook, Outlook Express or Exchange, the email will be wrapped in a Winmail.dat file.

Therefore, a Winmail.dat is a file including the email subject, recipient, sender, message body and attachments with good formatting. And it can be opened by Microsoft mail clients only.

For users who don't use Microsoft mail clients, a 3rd party Winmail.dat opener will be needed to view its contents.


The Best App for Opening Winmail.dat on Mac

Cisdem Document Reader ($9.99~$29.99)

Recommended by authorities like New York Times and CNET, Cisdem Winmail Viewer is always picked as the best app for opening Winmail.dat files on mac.

Cisdem Winmail Viewer for mac ($9.99) is a one-stop solution to open winmail.dat files on Mac and allows any attachments contained in them to be previewed and saved. No matter how large the Winmail file is, Cisdem can load and open it fast and well. Besides, it enables users to open multiple Winmail.dat files under different tabs at the same time, so you can switch between and compare all files for your purposes.

While, its full version, Cisdem Document Reader ($29.99), not only supports opening Winmail.dat files, but also allows viewing WPD, WPS, Visio, OXPS/XPS, DjVu, PDF files on Mac. With a set of viewing tools, you can open and view all these supported files comfortably. Still, it provides extended features, like rotate, bookmark, search, extract images, convert to PDF/Text/Image format.

How to Open Winmail.dat on Mac with Cisdem?

  1. Download and install Cisdem Document Reader on your mac;
    Free Download
  2. Drag and drop one or more Winmail.dat files to the program;cisdem winmail.dat viewer for mac02
  3. Open and view Winmail.dat files on mac.
    You can use the viewing tools (View, Bookmark, Page, Zoom, Turn Page, Rotate, etc.) to read the files as needed.cisdem winmail.dat viewer for mac01


3 Top Third-Party Winmail.dat Viewer for Mac

TNEF's Enough (Free)

With a 19-year history, TNEF’s Enough from Josh Jacob has served countless users on Winmail.dat solution. It is a program allowing users to read and extract files from Microsoft TNEF stream files, including Winmai.dat and application/ms-tnef. It works on latest macOS 10.15 Catalina and earlier.


  1. Support Mac OS X 10.15 and earlier;
  2. Allow opening Winmail.dat and application/ms-tnef;
  3. Free;
  4. Easy to use;


  1. Cannot open and view Winmail.dat directly in the app, you have to save the files first;
  2. Fail to open Winmail.dat files sometimes;
  3. Poor tech support;


Letter Opener for macOS Mail ($29.99)

Letter Opener for macOS Mail is a plugin for Apple Mail to directly display and convert Winmail.dat files. That’s to say, even the Winmail.dat emails can be viewed and processed the same way as other emails in your Apple Mail. There is no need to go back for composing emails in other email clients after displaying the Winmail.dat file. In addition, it supports multiple languages, including Arabic, Chinese, Dutch, French, German, Hindi, etc.


  1. Display and convert winmail.dat file inside OS X Mail;
  2. Directly process (edit, reply, forward, copy, search) Winmail.dat emails in Apple Mail;


  1. Doesn’t support latest macOS 10.15 Catalina;
  2. Too expensive for what it does;


MSG Viewer for Outlook ($17.99)

MSG Viewer for Outlook 3.99 is another app for opening Winmail.dat files on mac. It lets you open those frustrating Microsoft Outlook MSG, OFT, and Winmail.dat files on Mac. Batch processing and conversion to native mac formats (eml or vcf) is also supported. What’s more, it helps to import and save contacts in vCards.


  1. Work on macOS 10.15 Catalina and earlier;
  2. Support opening Winmail.dat and MSG;
  3. Convert files to native mac formats;
  4. Import and save to vCards;


  1. Interface is not that user-friendly;
  2. The trial version has 20-second delay to display messages;
  3. Cannot show attachments in emails with digital signatures or encryption;


Extended: How to Open Winmail.dat Files on iPhone/iPad?

To open Winmail.dat files on iPhone or iPad, a third-party Winmail.dat viewer is also required.

In fact, when discussing on what is the best app for opening Winmail.dat on macOS as above, the tools we listed also is available for iOS, for example Letter Opener for iOS. It is free to download and try, but offers in-app purchase for full features.

Main Features:

  • Open and view Winmail.dat files;
  • Convert to iOS native formats;
  • Export files to another app;

How to Open Winmail.dat Files on iPhone?

  1. Go to AppStore, download and install Letter Opener for iOS;
  2. Tap the Winmail.dat file and open with Letter Opener;
  3. View, convert or export the Winmail.dat file on your iPhone as needed;winmail.dat viewer for iphone


You can choose any one of these 4 top apps to open Winmail.dat files on your Mac. But after a thorough comparison on their features, user experience and prices, it’s no doubt that Cisdem Document Reader for Mac would be the best Winmail.dat opener for mac 2020.

Just have a try on the free trial version and open your Winmail.dat files quickly and easily.

Free Download

What’s your best app for opening Winmail.dat files on Mac? Is it on our top list? Please share with us in the comments.

Jose Henline
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Jose specializes in reviews, how-to guides, top lists, etc. on PDF, data recovery and multi-media. On his spare time, he likes to travel or challenge some extreme sports.

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  • Amy

    Thanks, I really like your posts. Each time you post a new article, I will take a look at it.

    5 years ago Reply

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