My client uses Outlook in conjunction with the ACT! contact list and history for each of their contacts. She has a specific few that continue to receive attachments as winmail.dat files. We have disabled RTF on the Exchange server and inside of her Outlook. When she types the addresses in directly into the 'to' box the recipients get the attachment just fine. When she chooses the contacts out of the ACT! contact list by clicking the 'to:' box to bring up the list, these contacts receive the winmail.dat files. I was unable to find a way to edit these particular contacts as they are not an Outlook contact list, they are the ACT! Contact list. Microsoft support blames ACT!. ACT! says its has to do with Outlook. My client is frustrated that neither of them can come to a conclusion and here I am. What are my options and how should I proceed?