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What's with these winmail.dat files??

Why am I getting a winmail.dat file with my emails?

It is not uncommon to receive an email that has a winmail.dat file attached to it. Sometimes an attachment you are waiting to receive will come as a winmail.dat file. When you go to open a winmail.dat file, your PC won't know what to do with it and so you are stuck unable to view the attachment.

A winmail.dat file comes from someone sending email through Outlook. Now obviously not every email sent from Outlook is received with a winmail.dat file. The reason for this is because it only happens when Outlook is sending email using the RTF format.

The RTF format means "Real Text Format". Instead of just using plain text, RTF allows you to change the font sizes, colors etc of your text. The problem is that Outlook stores the information regarding all the text enhancements into a winmail.dat file. It will also sometimes store attachments in these winmail.dat files as well.

When someone opens the email at the other end in Outlook it will convert the winmail.dat file back into the bold, blue text (or whatever was done to the text) and put any attachments back as it should be. The trouble comes when an email client at the other end isn't Outlook. It will likely not know what to do with the winmail.dat file, and so you see it simply as a winmail.dat file.

To stop Outlook from sending a winmail.dat file, Outlook needs to be set not to use the RTF format. This doesn't necessarily mean you can only send email in plain text to avoid the problem. Outlook also has an HTML format available that allows the same kind of text enhancements without requiring Outlook to send a winmail.dat file.

If you are the person receiving the winmail.dat files and you can't really tell the other person to change their email format, you can download a free program that will allow you to open a winmail.dat file. The program is funnily enough, called Winmail Opener and can be downloaded from here.

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