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. Right-click the DAT file on your PC and click "Open." ...

You can open .DAT files that contain text, with text editors, like Notepad, Notepad++, VS Code, etc. But it is not possible to know what contains in a DAT file.

Learn how to import or export data from a Text file to convert a Text (.txt or .csv) file into an Excel (.xlsx) spreadsheet easily using this procedure.