4 Ways on How to Open Winmail.dat on Mac, Free Included

Bianca Huang
August 18, 2022 Preview 16.3K Preview 1
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For Mac users, you might receive emails with .dat file extension but don’t know how to open this Windows-friendly file format on an Apple computer, including the latest iMac, MacBook Air, MacBook Pro. This article will show you how to open Winmail.dat file on Mac in 4 different ways, including several free ways. If you need a basic understanding about Winmail.dat format, you can jump to the end of this article first, then pick one of the best solutions to open yours.

How to Open Winmail.dat and Its Attachment Files on Mac

To open Winmail.dat files on a Mac, a Winmail reader is needed. Though not that large in quantity, there are still some top Winmail viewer for mac available for choice.

No matter you are a seasoned or newbie Mac user, Cisdem Document Reader is highly recommended for installation on your Mac. It is a top-notch solution for you to open Winmail.dat files on Mac, and allows any attachments contained in the Winmail.dat files to be previewed or downloaded to your computer. Even, it lists all the files in list view under one window, so you don't have to switch among different windows when opening multiple Winmail.dat files at the same time.

More than just a Winmail.dat Reader for Mac, Cisdem Document Reader is also a kit helping open different documents simultaneously on Mac, such as XPS, OXPS, WPD, WPS, VISIO, PDF and DJVU, with a set of tools offered to optimize reading experience. Besides, it can precisely present the original text style, graphics, hyperlinks, layout, images and formats.


  1. Easy to use
  2. No ads, high security and no leakage of email privacy
  3. View Winmail.dat directly without downloading
  4. Open Winmail.dat files quickly in batches
  5. No file limit

In additional, Cisdem Document Reader provides users with extended features to well manage these files, such as:

  • Extract images from supported files
  • Print out as papers or print as PDF
  • Export supported documents to PDF, Text, JPEG, PNG, RTFD, ect.  For example, converting VISIO to PDF, WPD to PDF, XPS to PDFDJVU to PDF, PDF to images and so on
  • Bookmark and search within files

Tutorial to Open Winmail.dat and Its Attachment Files on Mac:

  • Step 1. Download and install Cisdem Document Reader on your mac. It is lightweight and safe to download.
    Free Download
  • Step 2. Click Open File or drag-n-drop to open Winmail.dat file on your Mac. You can open and view multiple Winmail.dat files at the same time, also can switch between multiple Winmail.dat files easily. open winmail on mac 02
  • Step 3. Use the toolbars to read Winmail.dat files on Mac. All contents of Winmail.dat, including email message and attachments will be presented.Preview the attachments and save them to your Mac.open winmail on mac 03

Check the video to open Winmail.dat file on Mac Now!

How to Open Winmail.dat File on Mac Free?

If you don’t need to open the Winmail.dat file on your Mac frequently, or if you don’t deal with a large number of files and prefer a free method, there are 2 free apps to open Winmail.dat files on Mac.

#1 TNEF’s Enough

It is a free Mac AppStore program to view Winmail.dat files and extract its attachments (.vcf, .ics, .txt, .html). But it if pitiful that it supports macOS 10.11 to macOS 10.15 only. 


  1. It’s free to use
  2. Support Mac, iPhone, iPad and iPod Touch
  3. No ads.


  1. Fail to open Winmail.dat files occasionally
  2. Poor tech support
  3. Does not support previewing files in the app

Tutorial to Open Winmail.dat File on Mac Free:

  • Step 1: Make sure you have download and install TNEF’s Enough app on your Mac first.
  • Step 2: Open the Winmail.dat file with TNEF’ Enough, view the text body and attachment size & file name.open winmail.dat file via tnef enough
  • Step 3. Double click on the attachment and download it to your Mac.

#2 Letter Opener

Letter Opener integrates with macOS Mail app to open a Winmail.dat file with its attachment. However, you can only open and view one Winmail.dat file per week.


  1. Integrate with macOS mail and convenient for replying or rewarding emails.
  2. Show detailed information contained in the file.


  1. Open only one file per week.

Tutorial to Open Winmail.dat File on Mac Free in Letter Opener:

  • Step 1: Download and install this app from Mac AppStore or its website.
  • Step 2: Open the app, drag and drop the Winmail.dat file to it.letter opener01
  • Step 3. View the Winmail.dat text message and its attachments.letter opener 02

How to Open Winmail.dat File on Mac Online?

Also, if you just need to open one or two Winmail.dat files and don’t want to specifically download third-party tools, you can utilize online free Winmail.dat reader. According to our test, Winmail.dat Reader is a convenient choice to view Winmail.dat file. It provides 2 ways for users to upload a winmail.dat file for viewing: choose from local computer or enter URL.


  1. It’s free
  2. No need to install any third-party tool.


  1. File size larger than 50MB is not supported
  2. Ads on the website and there is a risk of information leakage
  3. The speed of opening files depends on network conditions
  4. Does not support batch open

Tutorial to Open Winmail.dat on Mac Online:

  • Step 1. Open your browser to https://www.winmaildat.com/, upload Winmail.dat files from computer or enter the URL.
  • Step 2. Click “Start” to get the winmail.dat file in RTF format.upload winmail.dat file to winmail.dat reader
  • Step 3. After that, the message body and original email attachment will display.download message body to your computer
  • Step 4: To open the RTF file, you need to download the message body first.

Is It True That We Can Open Winmail.dat Files on Mac in Gmail?

No, Gmail cannot open and view a Winmail.dat file.

I noticed that many bloggers recommend users to open and view Winmail.dat files in Gmail, so I followed the instruction by sending the file via email, then tried to open it with connected app in Gmail.

open winmail gmail01

But only garbled texts were displayed. There, Gmail doesn’t worl to open a Winmail.dat file, at least in my case.

open winmail gmail02

The Basics: What is Winmail.dat Format?

I sometimes receive e-mail messages with a “winmail.dat” file attached that I cannot open. Why does this happen, and what can I do to fix it?

The winmail.dat file exist because various email programs cope with message formats differently. Winmail.dat file is a proprietary email format created by Microsoft/Windows Exchange Server, which contains rich-text formatting and packs all the original email information (subject, body, attachment) in the file. Non-Microsoft email systems cannot recognize rich text format, which causes the original emails to be packaged as Winamil.dat attachments, and therefore users cannot open the Winmail.dat file directly. 


For sure, there are more options out there to open Winmail.dat files on Mac. However, in the light of the simplicity, performance and feedback from users, most users pick Cisdem Document Reader as the ideal program to open and view Winmail.dat files on mac. 

Now, try Cisdem Document Reader, then all your problems will be gone.

Free Download

Bianca Huang
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Bianca is a senior tech editor and strategist at Cisdem with Over 10 years of experience on PDF related solutions which covers all document editing, annotating, converting and managing etc.

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  • Doras

    Great tool, I can also view the attachments of winmail.dat files. Thanks.

    8 years ago commonReply

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