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

If you're having trouble opening a DAT file, I'll show you a simple and free way to do it. This method works on both Mac and PC. Just open your browser and go to winmaildat.com. It's a ...

If you can’t convince the sender to use standard email formats, you also have a few options for reading these Winmail.dat-formatted messages. On the Mac, TNEF’s Enough, can open winmail.dat files.

Right-click the DAT file on your PC and click "Open." Click "Select a program from a list of installed programs" and click "OK". Click "Microsoft Excel" from the list of programs on your computer.

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