How to Fix File Explorer Thumbnails Not Showing in Windows 11

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My Technician
Windows 11TroubleshootingShellFix

The Problem

Folders full of JPG and MP4 files display only generic icons—no picture previews in medium or large icons view. Explorer itself works; previews broke after a cleanup tool, low disk space, or a corrupted thumbcache database.

Explorer crashes or hangs? Fix File Explorer crashing. C: drive nearly full? Free up disk space—thumbnail creation stops when space is tight.

Symptoms

  • Large icons view still shows flat icons.
  • New files never get previews; old folders used to.
  • Previews work in the Photos app but not in Explorer.

The Fix: Step-by-Step

Step 1: Turn On Thumbnails in Folder Options

  1. Open File Explorer → ⋯ menu → Options (or View → Options).
  2. View tab → uncheck Always show icons, never thumbnails.
  3. Apply → OK. Open a picture folder → View → Large icons or Extra large icons.

Step 2: Per-Folder View Reset

In the affected folder: View → Large icons → Options → View → Reset Folders (applies default to all folders of this type). Test one image folder on the desktop before changing every library.

Step 3: Clear and Rebuild Thumbnail Cache

  1. Close all Explorer windows.
  2. Settings → System → Storage → Temporary files → enable Thumbnails → Remove files.
  3. Or manually delete cache (hidden files):
    • Press Win + R → %localappdata%\Microsoft\Windows\Explorer → delete files named thumbcache_*.db and iconcache_*.db.
  4. Task Manager → Windows Explorer → Restart (or reboot).

Step 4: Disk Space and Storage Sense

Thumbnails fail silently below ~1 GB free on C:. Free up disk space and pause aggressive Storage Sense that deletes caches daily: Settings → System → Storage → Storage Sense → adjust cleanup schedule.

Step 5: Default Apps and Codecs

Explorer uses installed codecs for video thumbs.

  • Settings → Apps → Default apps → set Photos for .jpg, .png; install HEVC extension from Microsoft Store if iPhone HEIC previews are missing.
  • Install official Video Extension packs if MP4 thumbs are blank but movies play in VLC.

Step 6: Performance Settings

Settings → System → About → Advanced system settings → Performance → Settings → ensure Show thumbnails instead of icons is checked under Visual Effects (custom mode).

Step 7: Group Policy and Registry (Pro / IT PCs Only)

If IT disabled previews, Local Group Policy Editor → User Configuration → Administrative Templates → Windows Components → File Explorer → Turn off the display of thumbnails → Not Configured or Disabled. Home users rarely need this—skip random registry scripts.

Step 8: System File Check

If Explorer also mislabels drives or icons:

sfc /scannow

Reboot and open the same folder again—wait 30 seconds for thumbs to regenerate on large libraries.

OneDrive and Network Paths

Online-only OneDrive files may show cloud icons until downloaded—Right-click → Always keep on this device for a test folder. Network NAS paths can be slow; Explorer may skip thumbs on laggy shares by design.

Still slow overall? Speed up a slow Windows PC if indexing and antivirus scan every new photo on import.