Letter Opener for Windows delivers a powerful Winmail.dat, MSG and EML file Viewer in an easy-to-use, modern app. Some people still use Outlook. And whenever they send you something like an attachment, it shows up in your Mail with a winmail.dat file attached. (Ugh.) But Letter Opener seamlessly converts all types of Outlook’s irksome winmail.dat files. (Hooray!) Made with a special 😤 for winmail.dat files.