HEIC files show no thumbnail previews
You can open the photos individually but the folder is a wall of identical grey icons, which makes finding anything impossible. The cause is usually the thumbnail cache, not the codec.
Check the obvious things first
- Are thumbnails switched on at all?
In File Explorer, open View → Options → View and make sure Always show icons, never thumbnails is unticked. Performance-tuning guides and some corporate images turn this on, which disables previews for every format, not just HEIC.
- Is the view mode showing icons?
Details and List views show file-type icons by design. Switch to Large icons or Extra large icons to see actual previews.
- Can you open a file?
If the photo opens in the Photos app, the codec is working and this is a cache problem — go to the next section. If it does not open, the codec is missing and thumbnails cannot work until that is fixed.
Clearing the thumbnail cache on Windows
Windows caches previews in a database that regularly becomes stale or corrupted, particularly after installing a codec — entries generated when the format was unreadable stay cached as blanks.
- Run Disk Cleanup
Press Win+R, type
cleanmgr, select your system drive, tick Thumbnails and click OK. - Restart Explorer
Open Task Manager, find Windows Explorer, and choose Restart. The cache rebuilds as you browse folders.
- Give it time on large folders
A folder of two thousand photos takes a while to regenerate. Leave the window open and scroll slowly rather than assuming it has failed.
macOS
Finder previews for HEIC are handled by QuickLook, which is built in. If they stop working:
qlmanage -r cache then killall Finder
If previews are missing only inside a particular folder, delete the .DS_Store file there
— it stores per-folder view settings and occasionally corrupts.
Linux
Install the thumbnailer alongside the library: sudo apt install libheif-examples
heif-gdk-pixbuf. Then clear the cache with rm -rf ~/.cache/thumbnails/* and restart
your file manager. GNOME Files, Dolphin and Thunar all use the same freedesktop thumbnail
specification, so one thumbnailer serves all of them.
When nothing else works. A persistently blank folder that resists every fix is usually a sign the files themselves are placeholders rather than real photos — iCloud stubs that were never fully downloaded, for example. Check the file sizes. If they are a few kilobytes rather than a few megabytes, the issue is the transfer, not the display.
Common questions
- Why do my HEIC files show blank icons?
- Either the HEVC codec is missing, so Windows cannot generate a preview, or the thumbnail cache contains stale blank entries from before the codec was installed. Test by opening one file — if it opens, it is the cache.
- How do I clear the thumbnail cache in Windows?
- Run cleanmgr, select your system drive, tick Thumbnails and confirm. Then restart Windows Explorer from Task Manager so the cache rebuilds as you browse.
- Why do thumbnails work for some HEIC files and not others?
- Files with unusual container structures — bursts, Live Photos, some Portrait shots — can defeat the thumbnailer even when ordinary photos work. Mixed results usually point to file variety rather than a broken installation.
- Do HEIC thumbnails work on Linux?
- Yes, once heif-gdk-pixbuf and the libheif thumbnailer are installed. Clear ~/.cache/thumbnails afterwards, since blank entries generated beforehand persist.