I was confused by your answer regarding winmail.dat. The file cannot be opened traditionally, at least to obtain what the receiver believes to be valuable contents. Rather, it's used internally by ...

Just open your browser and go to winmaildat.com. It's a straightforward website that lets you upload and open DAT files without needing to sign up or provide an email.

We keep getting e-mail attachments in winmail.dat files, and can't open them. What's going on? Is there a utility that can extract the attachments from these?