When File Explorer shows blank squares or generic icons instead of your photos, browsing a folder becomes guesswork. Thumbnails break for a few predictable reasons in Windows 11. Here is how to get them back, including for HEIC, AVIF and RAW files that Windows cannot preview on its own.

Fix 1: Turn thumbnails back on

A single setting can disable them:

  1. Open File Explorer and go to View > Options (or search "File Explorer Options").
  2. On the View tab, untick Always show icons, never thumbnails.
  3. Click Apply. Thumbnails should return.

Fix 2: Rebuild the thumbnail cache

A corrupted cache is the most common cause:

  1. Open Disk Cleanup.
  2. Tick Thumbnails (you can untick the rest).
  3. Click OK to clear it, then reopen the folder so Windows rebuilds fresh thumbnails.

Fix 3: Check performance settings

  1. Search Adjust the appearance and performance of Windows.
  2. Make sure Show thumbnails instead of icons is ticked.
  3. Apply and reopen Explorer.

Why HEIC, AVIF and RAW thumbnails stay blank

Even with everything above set correctly, some formats never show thumbnails because Windows cannot preview them without extra software: HEIC needs the HEIF extension, AVIF needs the AV1 extension, and RAW needs the Raw Image Extension. Each one is a separate install, and they are often slow.

A simpler way to see every photo is to browse the folder in an image viewer that makes its own thumbnails. HawkView shows a fast gallery of every image in a folder, including HEIC, AVIF, JPEG XL and RAW, without relying on the Explorer cache or any Store extension. If a specific format is the problem, our guides on opening HEIC and opening AVIF go deeper.

The bottom line

Re-enable thumbnails, clear the cache, and confirm your performance settings. For modern formats Windows cannot preview, browse them in a viewer like HawkView that generates its own thumbnails instantly.