If you mean a Winmail.dat then tell the person who is sending you
these with Outlook to uncheck the box :"Always send messages in
Microsoft Exchange rich text format."
I delete all winmail.dat files and ask the Outlook sender to change
from Rich Text to Plain Text.
I opened a few and found nothing of use inside.
This will open them if there is anything of use inside.
Fentun
http://www.fentun.com
A little more about them in the Eudora FAQ
WINMAIL.DAT attachment to messages
http://www.eudora.com/techsupport/kb/1552hq.html
and from MS:
How to Prevent the Winmail.dat File from Being Sent to Internet Users
http://support.microsoft.com/default.aspx?scid=kb;en-us;138053
....Alan