For example, the file extension.txt has an extension of .txt. This extension allows the operating system to know what type of file it is and what program to run when you double-click on it.

When you open files that have a particular file extension, Windows will look at its configuration to determine what the default program should be in order to work with these files. The default ...

How to Open Unrecognized File Extensions. In most cases, the majority of the file extensions you encounter on your computer are already associated with a program or protocol. When a file extension ...

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.

If you cannot associate file extension to application & see The program you selected cannot be associated with this file type error, see this fix.

You can create a file without a File Type Extension in Windows 11/10 by carefully following the steps laid down in this post.