a while back. Here's what he said:
Winmail.dat attachments are caused when the receiving client can not interpret Outlook's Rich Text Format. This would basically be every e-mail client other than Outlook. Send your messages in HTML or Plain Text format instead of RTF and the problem will not happen.
In your Tools | Options click the Mail Format tab and change it to HTML (or Text only). In your address book put a check in the "text only" check box for those not wanting to receive HTML mail (if you selected HTML previously).
Here is a KB article that explains what is happening:
Posted by: Edward O'Daniel (see profile) - 03/08/2005 10:51 AM
In reply to: Recipients are getting my attachments as .dat files by Supdev
Hope this helps you.
Hello! Once again I turn to my very patient experts...
I use Windows XP and MS Office 97. I get e-mails through AOL and hotmail. A client attached a file to an e-mail he sent simultaneously to both my screen names to be sure I'd get it. In both AOL and hotmail, the attachment is labeled: winmail.dat
In AOL, the text of the attachment appears in the body of the e-mail message, but I really need to see the graphs and charts in the original document which did not come through with the text. I cannot figure out how to open the winmail.dat file. The client says he received it as a winmail.dat file so he can't send it to me in any other format.
Thank you for any assistance you can give to me.