what software is needed to open a .dat file
Winmail Opener is a small and simple utility that allows you to view and extract contents of. -encoded messages (infamous winmail.dat). That means if you receive winmail.dat on your e-mail, with Winmail Opener you can view the rich text message contents and attachments embedded into this file. You may receive winmail.dat files from the senders who are using Microsoft Outlook (97, 2000).