When a file extension is not associated with a program, however, you are prompted by a "How do you want to open this type of file" or "Windows can't open this file" dialog when you try to open it.

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

Red Eye Rose received a file with a strange extension. She doesn’t know into what program she should load it. Neither does Windows. I doubt that anyone knows all of the file extensions used ...

Learn how to rename all file extensions in a folder & sub-folders at once on Windows 11/10. You can batch rename or rename all file extensions in bulk using this guide.

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.

Tick the checkbox next to Always use this app to open .ext files, where .ext is the extension of the file you’ve selected. E.g., .txt for text files, .jpg and .png for image files.

You can also change that extension’s default program (the one that launches when you double-click a file). In Windows XP, Vista, and 7, right-click the file and select Open with>Choose default ...

If you have an iPhone or iPad, it's easy to open HEIC image files on a Windows PC. We show you how in this guide.

On Windows 10, it's possible to open HEIC and HEVC files, but you'll have to install a couple of free extensions, and in this guide, I'll show you how. The High-Efficiency Image File Format (HEIF ...