[ winmail.dat or no attachment ] Outlook 2007 / 2010 Send Out E-Mail Problem

Cause ：
- When you use Microsoft Office Outlook 2010 or Microsoft Office Outlook 2007 to send an email message, the recipient of the message sees an attachment that is called Winmail.dat. This article helps you fix the problem.

- Forward E-Mail without any attachment, but recipient see the mail have much empty line and included "winmail.dat" attachment.

Resolution :
Download and Run Microsoft Fix it 50041

Source :
From Microsoft  http://support.microsoft.com/kb/958012