recommend app to open winmail.dat attachments?

Hi sharpeilady!

Thanks for asking.

Both Microsoft Outlook and the Microsoft Exchange Client sometimes use a special method to package information for sending messages across the Internet. This method is technically known as Transport Neutral Encapsulation Format (TNEF).

A TNEF-encoded message contains a plain text version of the message, and a binary attachment that "packages" various other parts of the original message. In most cases, the binary attachment is named Winmail.dat, and may include the following information:

• The formatted text version of the message (for example, font information and colors).
• OLE objects (for example, embedded pictures and embedded Microsoft Office documents).
• Special Outlook features (for example, custom forms, voting buttons, and meeting requests).
• Regular file attachments that were added to the original message.

You could try TNEF's Enough for macOS

Thanks for asking Communities.

Please let us know if you have any questions related.

If you have just few emails with winmail.dat attachments, probably you don't need any app.

You may ask to resend those emails again, but often there is no important information in those attachments.