We have just moved from an in house 2003 exchange server to a hosted exchange service. There are a few people that when they send PDF attachments the recipient receive them as a winmail.dat file. This happens to users on Outlook 2007 and 2010. If they log into the webmail and send the PDF they receive it just fine. This points me to an Outlook issue or setting. I do know that hosted server is Exchange 2010. Does anyone know what the issue may be, and how to fix it?