For years, J'ai eu the exact same issues with app thumbnails. Particularly for Metro-style apps (RT/UWP), Je souvent see a blank or default icon, primarily in search results and settings. I've been troubleshooting it for years, with no success until now. I'm documenting this here because Je sais I'm going to encounter it again. Quand je search for a solution, I'll hopefully find this page.
Background
In Windows 10, UWP apps are shipped as AppX packages. This includes many of the new built-in apps (stored in %SystemRoot%\SystemApps) aussi as apps downloaded via Windows Store (stored in %ProgramFiles%\WindowsApps). PowerShell offers several cmdlets that are useful for managing AppX packages. Throughout my troubleshooting, J'ai trouvé Get-AppxPackage, Add-AppxPackage, and Remove-AppxPackage particularly useful, especially since %ProgramFiles%\WindowsApps is inaccessible to normal users, even administrators.
Before attempting these fixes, vous devriez be comfortable editing le registre, working with the invite de commandes and PowerShell, and making backups. Vous devriez be prepared to wipe everything and reinstall Windows should something go wrong.
Issue 1: Third-party thumbnail handlers for .png
Some third-party apps like to install custom thumbnail generators. Some of these apps do so in a way that breaks things. Dans mon cas, Google's Drive File Stream was the culprit. Gardez à l'esprit that this is different from having a default program for a file; Windows Photos remained the default for me. To solve the issue:
Run: regedt32.exe
Navigate to: HKEY_CLASSES_ROOT\.png
Look for a ShellEx key with au moins one subkey. If you see any subkeys, you've probably found the culprit.
Delete the subkeys.
Restart Explorateur de fichiers.
Here's a screenshot of what vous devriez be deleting. Notez que the actual key might not be named {E357FCCD-A995-4576-B01F-234630154E96}; it'll depend on the application responsible for the issue.
This may seem like an obscure fix, but the issue stems from the fact that AppX package logos are typically stored as PNG files. When this issue arises, you may also notice that PNG files are lacking proper thumbnails (you won't see previews while browsing folders in Explorateur de fichiers). If the app causing the problem has installed similar handlers for other image type de fichiers, vous pouvez perform the same steps as above to the affected extension de fichiers to restore the thumbnails. Gardez à l'esprit that this may affect the functionality of the app, so you may have to make a trade-off.
Issue 2: Thumbnails are disabled in Performance Settings
Faites un clic droit sur the menu Démarrer icon or press Windows + X.
A menu will appear. Click System.
Under the Related settings pane à droite, cliquez sur le Advanced system settings link (System info link on older versions of Windows 10).
On newer revisions of Windows 10, the Advanced tab should already be selected in the resulting dialog. Si vous êtes on an older revision, cliquez sur le Advanced system settings link in the pane à gauche.
Click Settings... in the Performance group.
Ensure Show thumbnails instead of icons is checked.
Issue 3: Thumbnails are disabled in Options des dossiers
Open a Explorateur de fichiers window.
In the View ribbon tab, cliquez sur le Options button à droite.
Select the View tab in the resulting dialog.
At the top of the list of checkboxes in the Advanced settings group, ensure Always show icons, never thumbnails is unchecked.
If it's already unchecked, try checking it, clicking Apply, unchecking it again, and clicking OK. Sinon, just uncheck it et cliquez sur OK.
Issue 4: AppX packages need to be reinstalled
Get-AppxPackage -AllUsers | ForEach-Object {if ($_.InstallLocation) {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml" -Verbose}}
Issue 5: Windows Settings Sync
I've heard that Windows Settings Sync has caused issues with icons for some people. J'ain't been able to reproduce this, but vous pouvez check whether it's the issue by disabling it temporarily. It's likely that there's either some underlying setting that's the true culprit; it may be resulting in bad icons being uploaded. Reportedly, this primarily affects search results in Cortana and the menu Démarrer.
Issue 6: Bad icons/thumbnails are cached
Run Disk Cleanup. (Vous pouvez search for it in the menu Démarrer.)
Check Thumbnails. Uncheck everything else. If cela fonctionne, vous pouvez stop.
Click OK.
Ouvrez le invite de commandes.
Attempt an automated icon cache clear: ie4uinit -show (prior to Windows 10: ie4uinit -ClearIconCache). If cela fonctionne, vous pouvez stop.
Kill File Explorer: taskkill /im explorer.exe /f
Delete a cache: del /f /q "%LocalAppData%\IconCache.db"
Delete more caches: del /f /q "%LocalAppData%\Microsoft\Windows\Explorer\iconcache_*.db"
If thumbnails were also problematic, delete those caches, too:: del /f /q "%LocalAppData%\Microsoft\Windows\Explorer\thumbcache_*.db"
Start Explorateur de fichiers back up: explorer
Issue 7: Low espace disque
Unsurprisingly, if your drive is almost full, Explorateur de fichiers will have issues saving thumbnails and will be rather unhappy about it. The solution here is to clear some space. Simple enough.
Issue 8: Windows is borked, proceed to panic
Anytime someone mentions this problem on Microsoft Answers, a Microsoft rep always recommends the same solution. I've never heard of it working for anyone, but it can't hurt to try. (Besides, if you contact Microsoft, they're going to tell you to do it anyway.) It could theoretically fix certain obscure issues.
Open Invite de commandes as an administrator.
Run: sfc /scannow. Look for any violations that could be related to the issue at hand.
Run: dism /online /cleanup-image /restorehealth
Restart the computer.
If this actually fixed anything, please be sure to leave a comment.
