Dave, there are a couple of people who send me email, and, consistently, their attachments don’t show up as neat “foo.doc” or “report.xls” but as the generic attachment winmail.dat. They don’t know why and I don’t know why. Worse, as a Mac user, I can’t figure out what to do with them. What’s causing these “winmail.dat” files and how do I decode ‘em?
I too have variously been plagued with this winmail.dat affliction, and as far as I can tell, the problem is that Microsoft Exchange servers use the mysterious winmail.dat method of encoding attachments that are sent from one Microsoft Outlook user to another through a Microsoft Exchange server.
Of course, you clearly aren’t using Microsoft Outlook for Windows (since it would have magically decoded the attachment, leaving you none the wiser), and are instead faced with trying to decode this mysterious attachment…
Again, from what I’ve read, the real fix is for the sender to make a few tweaks to their Microsoft Outlook to ensure that their copy of Microsoft Exchange doesn’t think it’s sending to another Outlook user. It’s easy: they just have to indicate in their address book entry for you that you cannot receive Rich Text Format (RTF) rather than the current setting which assumes that you can and therefore must be running Outlook! Getting your colleagues to change their address books so that you have an easier time with their attachments might be, um, a bit tricky, however.
To simply unpack the attachments on your Mac, pop over to VersionTracker and search for “winmail.dat”. Surprise! You’ll find a link to a great little freeware app called TNEF’s Enough from Josh Jacob. Download and install it and you’ll be able to drag and drop these annoying winmail.dat files onto the app and have them unpack without incident.
That should solve your problem, or at least help you keep a tenuous grip on your sanity! Good luck.