Table of Contents

1. What is the Winmail.dat
2. How to stop sending Winmail.dat files
3. Viewing winmail.dat files

What is the Winmail.dat file

On occasion you may receive a strange attachment in your email called Winmail.dat. When you try to open it Windows will not let you, and the person sending it to you has no idea what it is. Do not worry, there are many people who have this same problem. The Winmail.dat is sent by users who use Microsoft Outlook as their email client and who have the send as Rich Text setting enabled. The Rich Text setting allows for all the original formatting including colors and fonts to be seen by the recipient of the email. The problem is that this is only useful for recipients who use Microsoft Outlook. If you are using Outlook Express, Netscape Messenger, Eudora, or a myriad of other email clients, then you will instead receive the Winmail.dat attachment.

How to stop sending winmail.dat files

If you use Microsoft Outlook as your mail client and have been receiving complaints that people are receiving these winmail.dat files from you, then it is easy to turn this feature off so this does not occur. To do so please follow these steps:

1. Start Microsoft Outlook.
2. Click on Tools.
3. Click Options.
4. Click on the Mail Format tab.
5. In the Send in this Message Format list, choose Plain Text.
6. Now click OK.

This make it so your default sending method will be plain text. By using this method you will no longer be able to use formatting, colors, or fonts, but you are guaranteed that everyone will be able to receive your emails as intended.

How to view the Winmail.dat files

If you are the recipient of Winmail.dat files and would like to be able to view them there are some programs that will allow you to do so. These programs will decode the winmail.dat file and allow you to view them as they were meant to be seen. Below I have listed a few programs that will allow you to decode the Winmail.dat files:

WMDecode

TNEF's Enough (For Mac Users)

As always if you have any comments, questions or suggestions about this tutorial please do not hesitate to tell us in the computer help forums.

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Lawrence Abrams
Bleeping Computer Microsoft Basic Concepts Tutorial
BleepingComputer.com: Computer Support & Tutorials for the beginning computer user.