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Windows 11 24H2 Shell Extension Bugs – Complete Troubleshooting Guide

Updated February 2026

Windows 11 version 24H2 brought welcome improvements to performance and security, but also introduced several bugs that affect shell extensions. This guide is a living document that tracks all reported bugs, their status, and available workarounds.

Bug #1: Explorer.exe Crashes When Opening Folder with Many Extensions

Affected builds: 24H2 early builds (before KB5048667)

Symptoms:

Root cause: 24H2 changed the COM apartment threading model for thumbnail generation from MTA (Multi-Threaded Apartment) to STA (Single-Threaded Apartment) in certain scenarios. Extensions that were thread-safe under MTA but not under STA crash with access violations.

Resolution: Install cumulative update KB5048667 or later. Microsoft reverted the threading change and added compatibility shims.

Workaround (if you cannot update):

  1. Switch slow folders to Details or List view (disables thumbnails)
  2. Disable thumbnail generation: Settings → System → About → Advanced → Performance → Uncheck “Show thumbnails”

Bug #2: Icon Overlay Priority Reshuffled

Affected builds: All 24H2 builds

Symptoms:

Explanation: Windows supports a maximum of 15 icon overlay handlers (this is a hard limit in the Windows Shell). The 24H2 update re-registered several Microsoft overlay handlers, pushing third-party ones below the cutoff.

Check your current overlay count:

$overlays = Get-ChildItem "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers"
Write-Host "Total overlays: $($overlays.Count) (limit: 15)"
$overlays | Select-Object PSChildName | Sort-Object PSChildName

Fix: Rename overlay keys to sort them alphabetically before Microsoft ones. Add spaces at the beginning of the key name (spaces sort before letters):

# Example: Prioritize TortoiseSVN overlays
# Run in elevated PowerShell
$svnOverlays = Get-ChildItem "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers" | Where-Object { $_.PSChildName -like "*Tortoise*" }
foreach ($overlay in $svnOverlays) {
    $newName = "  " + $overlay.PSChildName  # Add 2 spaces
    Rename-Item $overlay.PSPath -NewName $newName
    Write-Host "Renamed: $($overlay.PSChildName) -> $newName"
}

Bug #3: Thumbnails Not Generating for Custom File Types

Affected builds: 24H2 builds before January 2025 patches

Symptoms:

Root cause: 24H2 introduced stricter signature checks for thumbnail providers. Unsigned providers or providers with expired certificates are silently skipped.

Diagnosis:

# Check if a thumbnail provider DLL is signed
$dll = "C:\Program Files\Adobe\Photoshop\PSShellExt.dll"
$sig = Get-AuthenticodeSignature $dll
Write-Host "Status: $($sig.Status)"
Write-Host "Signer: $($sig.SignerCertificate.Subject)"

Fix:

  1. Update the software that provides the thumbnail handler
  2. If no update is available, clear the thumbnail cache and try again:
Stop-Process -Name explorer -Force
Remove-Item "$env:LOCALAPPDATA\Microsoft\Windows\Explorer\thumbcache_*.db" -Force -ErrorAction SilentlyContinue
Start-Process explorer

Bug #4: Context Menu Items Not Appearing After Clean Install

Affected builds: 24H2 clean install (not upgrade)

Symptoms:

Root cause: Fresh 24H2 installations use a different COM registration database location. Some installers write to the old location.

Fix:

  1. Reinstall the affected software after 24H2 is already installed
  2. If that does not work, manually register the DLL:
# Run as Administrator
regsvr32 "C:\Path\To\SomeExtension.dll"

Bug #5: “Show more options” Context Menu Empty or Incomplete

Affected builds: Intermittent on all 24H2 builds

Symptoms:

Root cause: This appears to be a timing issue. If Explorer takes too long to enumerate classic menu handlers, it shows whatever is ready before a timeout.

Workarounds:

  1. Press Shift+F10 instead (sometimes loads faster)
  2. Restore the full classic menu permanently:
reg add "HKCU\Software\Classes\CLSID\{86ca1aa0-34aa-4e8b-a509-50c905bae2a2}\InprocServer32" /f /ve
  1. Reduce the number of context menu handlers to speed up loading

Bug #6: Drag-and-Drop Shell Extensions Fail Silently

Affected builds: All 24H2 builds

Symptoms:

Root cause: 24H2 added new drag-and-drop security checks that reject drop targets in certain COM configurations.

Status: Microsoft acknowledged this bug. Fix expected in a future cumulative update.

Workaround: Use clipboard (Ctrl+C / Ctrl+V) instead of drag-and-drop for affected workflows.

Diagnostic Checklist

If you experience any shell extension issues on 24H2, run through this checklist:

Frequently Asked Questions

Q: Should I wait before installing 24H2? A: In February 2026, most bugs are patched. Install the latest cumulative update immediately after the 24H2 upgrade.

Q: Can I roll back to 23H2? A: Only within 10 days of the upgrade (Settings → System → Recovery → Go Back). After that, you need a clean install.

Q: Are there any shell extensions that work better in 24H2? A: Yes — extensions that implement the new IExplorerCommand interface integrate more deeply with the new context menu and perform better than legacy handlers.

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