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 ...

What is the deal with those winmail. dat files? I get them in my email all the time, and nothing seems to be able to open them.

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

What is the location of NTUSER.DAT file? Can you delete the NTUSER.DAT file? How does it work? This post answers all these questions and more.

If the DAT file you're trying to open is text, you can convert the file into text in the Microsoft Excel program by first saving it as a CSV file.