Show File Extensions & Change What Opens Your Files

Last updated: May 25, 2025

Show hidden file extensions in File Explorer, change file associations, rename file types, and learn to identify dangerous file extensions for security.

Overview

Can't tell what type your files are? This beginner guide shows how to reveal file extensions, change which app opens each type, and spot dangerous files.

What this helps with

What to expect: Easy difficulty • usually about 5 minutes.

This is one of 59 Beginner Essentials fixes in the WindowsHelper library. The full step-by-step fix lives in the WindowsHelper app.

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