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

Q. I sometimes receive e-mail messages with a “winmail.dat” file attached that I cannot open. Why does this happen, and what can I do to fix it? A. The winmail.dat file usually appears because ...

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 ...