Winmail.dat: what is this file and how to open it

Having received the next letter by e-mail, any user may face the situation when some information in this letter is missing and in the same time there is winmail.dat is in the list of files. This file can be downloaded to your computer without problems, but you will not be able to open it with standard tools. At the same time, a winmail.dat may contain a very important information, because, in fact, this file can be called a data archive of some kind. In this article we will find out why winmail.dat may appear in the list of files and what is the best way to open it.

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Table of contents:
1. Winmail.dat in the letter: what is this file
2. How to open the winmail.dat file
- Using online services
- Using utilities

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Winmail.dat in the letter: what is this file

If the sender sends his message using Microsoft Outlook, Express or Exchange (or other less common third-party programs), some of the information in it can be sent in an attachment named winmail.dat. Also on the Internet you may meet another name for this file – it can be called TNEF, which is the abbreviation for Transport Neutral Encapsulation Format.

This winmail.dat file mainly appears because when the sender was using his application to send the message, he applied formatting that is not supported by the program (for example, the browser) that will be used by recipient to view this message. At the same time, the letter from the sender left in the RTF format. As a result, the recipient will find only some text and attached supported materials from the sent message, but the formatting elements (font, color), vcf contact cards, icl calendar events and some other elements will be placed in a file named winmail.dat.

How to open the winmail.dat file

Having received the winmail.dat file in the letter, any user can open it, if necessary, even without having an Outlook e-mail client (or anything like it, supporting operations with this file) on his computer. It is possible to use online services or special small utilities to view information in the winmail.dat file.

Using online services

There are many online services that will allow you to easily extract information from the winmail.dat file. One of the proven and convenient services is Winmaildat.com. It’s interface is not overloaded with unnecessary features, you can work with it for free, and it copes with it’s main task – opening the winmail.dat file –  without any problems. This service operates as follows:

1. First you need to download the winmail.dat file from the letter that you received;
2. Next go to the Winmaildat.com website and click “Choose a file”. In the window that opens, specify the path to the winmail.dat file downloaded on your computer;
3. When the file is downloaded, click “Start” and wait. Waiting time depends on the file size and connection speed;
4. After a while the page will be updated, and you can download all necessary files to your computer. It is worth noting that the online service in question does not work with files that weigh more than 10 MB.

Using utilities

There are several programs to view winmail.dat files, created for various operating systems, including mobile ones:

• Windows. If you have a permanent need to open winmail.dat files, it is advisable to install a special application that performs this function on your computer, instead of using the online service. The program called Winmail Reader handles the task of viewing the winmail.dat files without any troubles. You can download it for free from the official website. It is worth noting that, unlike the online service mentioned above, this program can work with files larger than 10 MB;
• MacOS. Mac App Store has a Winmail.dat Viewer application. It is called Letter Opener 4 and it also serves to open winmail.dat files. This program is extremely simple and free. It has a very convenient content preview function;
• iOS and Android. You can also easily find programs for mobile operating systems that will allow you to open winline.dat files. Winmail.dat Opener is an extremely simple and convenient application for Android, and at iOS-devices you can use Winmail DAT File Viewer.