Outlook 2007 Clients receiving winmail.dat attachments

Question

 I am running Exchange 2007 on Windows 2003 R2 64 bit.  End users run Outlook 2007 on XP  sp2 machines.  Users randomly receive winmail.dat attachments in their email.  Does anyone know how to fix this on Exchange 2007?

Answer 1

That is what I find most interesting, is what Microsoft has released regarding winmail.dat files.  It seemed to me that it was the mail compliance of the recipient that was causing these files to appear.  Only recently have I found more discussion on the topic on other forums, including here, showing that it is also caused by other situational basis other than the recipients method of viewing the email...unless I misunderstood all along and it would seem so.  Because in my mind, it would make more sense if the recipients mail server is the cause of the issue, not so much the recipient.  if the recipients mail server does not interpret TNEF than could all their customers be experiencing this?  i must assume this because it would mean that if the recipient accesses their email via a webmail client that does not support TNEF, than they receive a winmail.dat...however if they check their email again from outlook or someform of email program that does understand TNEF, than shouldn't the email and attachments show up properly?  It is my experience that they do not.  That is how I began thinking that it must be the mail server of the recipient that is causing this.
I tried setting the 1 user's outlook to send only plain text...I am waiting to hear the results, but they were already set to send in HTML only.  By my understanding is that TNEF is created only when RTF is used for outbound email, and HTML and Plain Text do not create TNEF...punch me if I'm wrong