For the last two years, whenever a certain person sends our office a PDF it arrives as a winmail.dat file. I assume it was a problem with his settings and just use TNEF to open them. His attachments are always winmail.dat on both iMacs in our office. This week we bought a third Mac for someone new in the office and the PDF attachments from the same person show up properly on the new mac. Even when all three Macs are CC on the same message, the two older Macs get winmail.dat files and the new one gets a perfect PDF. Any ideas?