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How to Open Winmail.dat Files on Mac

There are people using Windows/Outlook, so you might receive emails with .dat file extension. Many Mac users have encountered the problem of failing to open winmail files on Mac. This article will show you how to open and view winmail.dat files on Mac by using a document reader.

The main content of this article consists of two parts:

What Is Winmail.dat File?

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 usually appears because various mail programs cope with message formats differently. Winmail.dat file,a proprietary email, created by Microsoft/Windows Exchange Server, which contains rich-text formatting. The problem is that the files can only be read by certain email clients.

How to Open Winmail.dat File on Mac?

There are two methods to address these tiresome troubles. One is to ask your Windows/Outlook friends to reset their mail formats. And the other is to download a winmail reader from App Store, then you can open those files without a hitch while you are on-the-go.

Here I recommend you Cisdem DocumentReader. It is an one-stop solution for you to open winmail.dat files on Mac OS, and allows any attachments contained in them to be previewed and saved. As described by his name, it can open different documents simultaneously on Mac, like XPS, OXPS, WPD, WPS, Visio, PDF and DjVu. DocumentReader can also let you extract images, print and convert the documents into PDF, Text, JPEG, PNG, RTFD, ect.

Read the instructions below on how to open winmail.dat file on Mac:

Step 1: Download and install DocumentReader.

Step 2: Click Open File or drag-n-drop to open winmail.dat file on your Mac.

Import DjVu files on Mac

Step 3: All contents of winmail.dat, including email message and attachments will be presented. With this product and its list view, you can open and view multiple winmail.dat files at the same time. Moreover, you are able to switch between multiple winmail files easily.

Download Cisdem DocumentReader now, and stop opening winmail.dat files without viewing the attachments. It works flawlessly, which makes you don’t even notice its existence.

Here are some complementary features of Cisdem DocumentReader:

  • It will open and list all the files in list view in one window, so you don't have to switch among different windows when opening multiple winmail.dat files simultaneously.
  • Not only can it open files, but support converting Visio to PDF, WPD to PDF, XPS to PDF, DjVu to PDF, PDF to images and so on.
  • When you open documents on Mac with the application, it precisely presents the original text style, graphics, hyperlinks, layout, images and formats.
  • With its fantastic toolbar, you can view, rotate, zoom, export and print files. If you would like to find a word in a file, you can use Keyword Search function.
  • It supports OS X 10.8 Mountain Lion or later.


There are many free products. However, in the light of the comments given by their users, their performance will disappointing you. And paid-for product like Letter Opener Pro ($29.95) is too costly. If two products work just about the same, why don’t we choose a relatively cheap one. Therefore, it is pretty much clear for us that Cisdem DocumentReader is ideal for non-Windows/Outlook users to read winmail files on Mac.

Have Cisdem DocumentReader installed now, then all your problems will be gone.

If you have any question or problem not covered in this article please leave a reply.

2017-01-11 01:53:55 / Posted by to Document Reader Follow @ Connie

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1 Responses

  • Doras

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

    1 years ago REPLY

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