I have to users both using Outlook for Mac  2011. An email comes in with an attachment which they are both CC'd. One of them gets the correct .pdf attachement, the other recieves a "winmail.dat" attachment. Now I know there are apps that will convert the winmail.dat, but i'm curious as to why if it is an issue with the windows user sending the email, why didn't they both have the same issue? Is there a setting that I can toggle to fix this?