Win mail dat

You're referring to the infamous "Winmail.dat" file!

The "Winmail.dat" file is a mysterious attachment that often appears in email messages sent from Microsoft Outlook or other Microsoft email clients. It's usually around 2-3 KB in size and has a.dat extension.

The file is not a document or an image, but rather a container for Microsoft's Rich Text Format (RTF) formatting information. When you send an email with formatting, such as font styles, colors, or images, Outlook converts the formatting information into a binary format and saves it in the "Winmail.dat" file.

The file is not intended to be viewed or opened by the recipient, but rather is used by the email client to preserve the formatting of the original message. However, some email clients, especially those that don't support RTF formatting, may not be able to display the message correctly, resulting in the "Winmail.dat" file being sent as an attachment.

If you receive a "Winmail.dat" file as an attachment, you can usually ignore it or delete it, as it's not a document or image that you need to view or open.