If you receive an attachment labelled winmail.dat on your Mac, it means that the message was sent from Microsoft Exchange and that you were inadvertently sent the message in an internal format intended for Microsoft Outlook users. This is not something that the sender explicitly chose to do, but rather a hiccup that can occur聽occasionally
Apple provides information on how you can contact the sender to adjust their聽Outlook settings so this does not happen again:
- Mac OS X Mail: What is a winmail.dat attachment?
However this is not always practical. Alternatively, there are聽a number of free and commercial聽OS X utilities intended聽to convert winmail.dat attachments to be readable on a Mac. Here is a sample free one:
- TNEF’s Enough,聽
References
- TNEF’s Enough,聽
- TNEF’s Enough 2.2 – Winmail.dat Decoder,聽
- Why am I receiving winmail.dat attachments?聽
- Open winmail.dat files on a Mac,