Winmail Reader is simply to use Windows application for reading winmail.dat attachment files. Winmail Reader allows to view, open or save the files contained on the Winmail.dat attachment. Simple and fast to use. Winmail.dat files are sent by the MS Outlook and other e-mail clients, like Thunderbird, cannot decode them. Version 1.1.11 may include unspecified updates, enhancements, or bug fixes.