If you have ever used OSX Apple mail to communicate with someone using hotmail, outlook enterprise/outlook office web access, etc. then you know that if they try to send you an attachment, the email that opens on your mac has no attachment and always has "winmail.dat" in the body of the email. The same is true on iOS. Apple has a support page where they just say "To avoid seeing these attachments in the future, ask the sender to turn off the option in their email app to send the message in Microsoft rich text format." I then always have to go to webmail to get the attachment. After so many iterations of OSX, why can't Apple implement a workaround for this. It is really frustrating for business users where Microsoft email clients are common.