[doctorZZ]

I'm currently working as a contractor for a company that uses an Exchange server for their email; I have an email account under their domain, which I access from my MacBook Pro Mail.app client (I'm using Snow Leopard). No problems for me, but there is another contractor who is using a MacBook Pro, Snow Leopard and Mail.app with a gmail account. Whenever I send him an email with an attachment, it shows up in his Mail.app as a winmail.dat file that he cannot open.
I know the problem is not with me - I can send emails to other gmail accounts with attachments without problems. Also, if he uses a web browser to access gmail the attachment is there. So, the issue is either with how gmail is passing along the attachment to him, and/or how his Mac is interpreting the file.
Neither of us have any idea on how to fix this, other than to rely on the web client, which we'd rather not. I'm guessing the problem is with the Exchange server, but it's being administered by a 3rd party company that "doesn't support Macs.". If I can identify a specific fix there's a chance it will be addressed, otherwise probably out of luck.
Help?
Thanks
DoctorZZ

[Cold Warrior]

Set your messages to plain text and send them this way. Winmail.dat is a byproduct of Microsoft Exchange and Outlook.
How to Prevent the Winmail.dat File from Being Sent to Internet Users
Winmail.dat attachments are included in received e-mail messages in Outlook

[P]

Alternatively, you can advice your colleague that he can use an app called TNEF's enough to decode those attachments.

Basically, Outlook adds a winmail.dat file to all messages sent with rich text formatting (bold or italic or similar), and if you attach a file to it, it bundles the file up in this winmail.dat as well. I get them at work every now and then as well (we use Notes) - almost as annoying as its failure to correctly wrap the sender name in quotes, so any name given as LastName, FirstName becomes two recipients in Notes. on't get me wrong, there are many reasons to hate Notes as well, but these two are due to Outlook.

[doctorZZ]

Thanks for the good advice, CW and P, but I still think (and hope) there's another way to fix things. I dislike Outlook as much as anyone, but if the problem was only the Exchange server making the attachment unintelligible to non-Win platforms, then the attachment should be bad for all. Recall, though, that if I send the same email to a gmail acccount that I own, then I'm able to access the Mail.app attachment just find (no winmail.dat for me). Also, my colleague is able to access the file using the gmail web interface. So, the problem requires the interaction of an Exchange server, gmail, and my colleagues computer.
He told me yesterday that he's also tried Thunderbird, and he still gets the winmail.dat file instead of the pdf attachment. I'm guessing this means there is some sort of unholy interaction between how gmail collects the attachment from the Exchange server, and then passes it along to a mail client.
Still hoping...
DoctorZZ