Select the .dat file you want to open in Excel. Finally, in the Text Import Wizard that opens up, select Fixed width, and then set the Field width and Data format when asked.

If you have a .DAT data file of unknown origin, your best bet is to open it with a text editor before you try anything else. There may be clues to its program of origin in the text.

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 ...