Though DAT files, which house data as the shortened name implies, are usually best left alone, here's how you can open them.

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.

Tips on opening a winmail.dat file, keeping seldom-used ink cartridges from drying out, and undoing an Undo.

Q. I received e-mail from a relative that says it is in a winmail.dat file. When I try to open the file, I get a message that says something like: "You are attempting to open a dat file. They are ...