Solved: Windows 11 Not Showing Video Thumbnails

If you recently noticed that Windows 11 stopped showing video thumbnails — especially for .mp4, .mkv, or .hevc/x265 files — you’re not alone. Many users experience blank icons instead of preview thumbnails after a Windows update or codec change.

Fortunately, the fix can be surprisingly simple.

In most cases, Windows 11 fails to generate thumbnails because its built-in video decoder (used by File Explorer) hasn’t initialized the correct codec yet.
You can trigger it manually by opening the video file once in Microsoft’s Photos app.

Steps:

1. Right-click on any video file that’s not showing a thumbnail.
2. Choose Open with → Photos.
3. Let it play for a few seconds, then close it.
4. Go back to File Explorer — the thumbnail should now appear instantly!

After this, Windows will usually start generating thumbnails for all other videos of the same type automatically.

When you open a video in the Photos app, Windows 11:

• Activates the HEVC/H.265 codec (used for modern video formats).
• Registers the correct thumbnail handler in the system.
• Refreshes the thumbnail cache for supported formats.

Once this initialization happens, File Explorer can use the codec to generate previews for all similar files.