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.

When you double-click on a file in Windows, it will automatically open a default program that is configured to manage these types of files. It is common, though, want or need to use a different ...

A CSV file is a simple text file that you can open in a wide variety of programs, including any program that works with plain text like the Notepad app.

You can open or import a surprising number of file formats into Microsoft Word. Not to be confused with file formatting, which—in most programs—refers to the design of a page, file formats are ...

If you double-click a file and it opens in the wrong program, try this: In Windows’ File Explorer, right-click a file with the extension you have in mind, and select Open with.

While you can manage that to-do list from the text file yourself, editing your to-do list in a flat text file using an editor like Notepad.exe or TextEdit isn't the fastest or most ideal way to do so.