Apr 10, 2011  Here are instructions on how to open the winmail.dat file: Save your winmail.dat file on your Desktop. If you use Mac OS X 10.6 or later then download the most current update of TNEF’s Enough version 3. If you use Mac OS X 10.5 then download TNEF’s Enough ver 2.2. If you use OS X 10.4 or earlier then download TNEF’s Enough ver 2.0. Winmail.dat Opener is a free app that allows you to open these files and view, save or share their contents. This app is free of charge and fully functional, without the need for further in-app purchases. The app requires only about 3mb space and no unnecessary permissions. Your files are processed on your phone and not sent to any external.

• Can't Open Winmail Dat Attachments

Did you receive an email attachment named winmail.dat or winmail? Here’s a brief explanation of what this file is and instructions for opening it.

Winmail.dat files are sent by people using Microsoft Outlook as their email application. Under certain circumstances Outlook will encode attached files, like Word or PDF files, in this winmail.dat format.

Update May 2012: If you need to open winmail.dat files on your iOS device (iPhone, iPad or iPod Touch) try Winmail File Viewer which currently costs 99 cents in the iTunes Store.

Update February 2017: In November 2015, an iOS version of TNEF Enough was released by the developer of TNEF Enough.

Mac users can open the winmail.dat file using a free application (donations accepted) and extract the files hiding inside. Unfortunately, this application has a goofy name which is TNEF’s Enough.

Here are instructions on how to open the winmail.dat file:

• Save your winmail.dat file on your Desktop.
• If you use Mac OS X 10.6 or later then download the most current update of TNEF’s Enough version 3. If you use Mac OS X 10.5 then download TNEF’s Enough ver 2.2. If you use OS X 10.4 or earlier then download TNEF’s Enough ver 2.0.
• By clicking on one of these links, you’ll download a .zip file which contains TNEF’s Enough inside. Your Mac should automatically open the .zip file so you should see TNEF’s Enough sitting in your Downloads folder.
• Move TNEF Enough into your Applications folder.
• Double-click it to open, then go to the File menu and select Open…
• Select the winmail.dat file which you previously put on the Desktop.
• You’ll then see a window listing the embedded files which are the files that you actually want.
• Click on each file, one at a time, and click the Save button.
• Save these files to your Desktop or any other desired location.
• Quit TNEF’s Enough.

You’re done. You can now throw away the winmail.dat file since you’ve extracted all of the files from inside it.

If you’d like to read more about how and why this happens please read this Microsoft Support article or this other article. These articles also provide instructions that you can pass on to the Outlook user who sent you the winmail.dat file so he or she can make changes to no longer send you winmail.dat files. Essentially, they have to edit their record for you in their Contact list to indicate that you should only receive plain-text emails.

Technology and You

Technology can be daunting, even with all the advances we have made. One of the most important things technology has brought us is a simplified and rapid means of communication, but sometimes, one form is incompatible with another. In instances like this, we find ourselves needing to adapt to the situation. One such instance is finding a file labeled “winmail.dat” attached to our email. What is it, and how do we read it?

What is Winmail.dat?

To begin with, the winmail.dat occurs when an email is sent via an improperly configured Outlook email app due to the use of rich text format within a transport neutral encapsulation format. The OS X app does not recognize this format, and therefore it does not translate properly when sent through email.

How Do I Read a Winmail.dat Attachment?

Reading one is simple, as the email will possess a text-based version of the attachment, making the attachment itself null. However, if opening the attachment and viewing it in full is desired, there are a couple of ways to go about it. Installing a converter program would be the best course of action.

Finding Converters

There are free converters that allow you to upload the winmail.dat file to be read on site, and the Mac App Store offers a conversion app (TNEF’s Enough) that will allow you to open the files on your Desktop.

Making the Choice

Can't Open Winmail Dat Attachments

It’s a matter of personal convenience which method to use. Converter apps take up memory space on our devices, and sifting through online programs can become tedious. Understanding that an email with a winmail.dat attachment will have an accompanying simplified text can be beneficial. Simply put, it is not necessary to add any new programs to your device unless you absolutely want to or unless the file is needed for presentation. In that instance, any of the above solutions is worth a look.