Do you use OS X Mail? So know what to do when you receive an attachment “winmail.dat”

If you have a Mac and use Mail (native OS X email client), you should have received an email in your life that was supposed to come with an attachment (image or document), but ended up with a such from winmail.dat. After all, what is that? And what to do to solve the problem without disturbing the person who sent you the email?

This Apple support article explains exactly what it is about:

Mac OS X Mail: What is a winmail.dat attachment?

You should ask yourself what is a winmail.dat attachment that Mail displays with the "question mark over text" icon.

The attachment means that the email was sent from a Microsoft email application (such as Outlook and Microsoft Exchange Client) and includes RTF information such as fonts, colors and special features such as underlined or bold text must appear in the email (the attachment in it appears in Outlook, but it appears in Mail, it can appear in other email applications like the MIME seo “application / ms-tnef”).

Apple's solution for Mac users to avoid these attachments by doing what we don't want: annoying the sender. If you are comfortable with this option, just ask the person to deselect the "Send to this recipient in Microsoft Rich Text format" checkbox or the preference setting in the email client before sending the message.

But if you simply want to solve the problem and view the blessed attachment, we have two tips.

Using applications

In the Mac App Store there are a multitude of applications for this purpose. Normally everyone works in a very similar way: you drag the winmail.dat file to the app window and it decomposes everything, showing the attachment you were actually waiting for.

Check out some apps like this:

WinMail DAT Viewer Pro app icon

Letter Opener app icon

Winmail Viewer - Open dat file app icon

Winmail.dat Viewer Pro Edition app icon

Winmail Decoder - The Best Winmail.dat Reader app icon

Winmail Extractor - Viewer for winmail.dat files app icon

Sorry, app not found.

Easy Winmail Reader app icon - extract attachment from winmail.dat

Winmail Reader-Lite app icon

Winmail DAT Explorer app icon - your Winmail.dat viewer

Winmail.dat Opener app icon: DAT Reader

Winmail Opener + app icon

Winmail Opener Pro app icon

Winmail.dat Opener app icon

Winmail.dat File Opener Plus app icon

Winmail Reader app icon

Sorry, app not found.

Winmail.dat to EML Converter app icon

Sorry, app not found.

Winmail.dat Unpack app icon

Sorry, app not found.

Quick DAT Viewer - for Extract attachments and rich text from Winmail.dat files app icon

Winmail-Extractor-Lite app icon

Sorry, app not found.

Sorry, app not found.

Winmail-View app icon

Sorry, app not found.

WinmailFileReader app icon

On the Web

Now, if you don’t even want to install an app for this, you can do it all over the web.


There are sites, such as Winmaildat, which extract winmail.dat files in a very simple and fast way. Just upload winmail.dat and the list of attachments will appear seconds later.