# Explorer freezes or right-click is slow: find the shell extension

> Diagnose Windows 11 Explorer hangs and slow context menus with Event Viewer, Reliability Monitor, clean boot and shell-extension isolation.

**Tested on**

- Build: 26300.9457
- Edition: Pro (26H2)
- Architecture: x64
- Evidence: E1
- Verified: 2026-10-28

## The short answer

Explorer hangs are often a **shell extension** (right-click menu, cloud sync, archive, PDF, antivirus) or a **driver/disk** problem, not “Windows being slow”.

Check:

1. Is CPU/disk actually busy?
2. Does it hang only on right-click, only on a folder, or everywhere?
3. What was installed/updated before it started?
4. Does a clean boot fix it?

## Evidence first

- **Event Viewer → Windows Logs → Application**: `Application Hang` / `Application Error` for `explorer.exe`.
- **Reliability Monitor**: the app/driver installed before the first hang.
- **Task Manager**: disk queue/CPU during the hang.
- **Safe Mode/clean boot**: if it disappears, it is a third-party component.

```powershell
Get-WinEvent -LogName Application -MaxEvents 100 |
  Where-Object ProviderName -match 'Application Hang|Application Error'
```

## Isolate shell extensions

1. Clean boot (`msconfig` → hide Microsoft services → disable all → reboot) for a test.
2. If Explorer is stable, re-enable half the non-Microsoft services, then narrow.
3. Use **Autoruns** (Sysinternals) → Explorer tab to see shell extensions; uncheck one at a time.
4. Right-click menu handlers live under `HKCR\*\shellex\ContextMenuHandlers` and `Directory\shellex\ContextMenuHandlers`; do not delete keys blindly.
5. Uninstall the offending app or update it; re-check after reboot.

> **Caution: Do not “clean” the registry with a one-click tool**
>
> Registry cleaners can remove legitimate shell handlers and make the problem harder to diagnose. Use Autoruns to disable, not delete, and keep a restore point.

## Other common causes

- **Cloud sync** (OneDrive/Dropbox/Google Drive) scanning a huge folder.
- **Antivirus** scanning on access; test with a narrow exclusion, not by disabling protection permanently.
- **Bad thumbnail/icon cache**: rebuild only after the extension check.
- **Failing disk**: Event Viewer `disk` errors, SMART warnings; back up first.
- **GPU driver**: Explorer uses the GPU; a bad driver can cause flicker/hang.
- **Network drives**: a disconnected mapped drive can block Explorer; disconnect it.

## If it is only one folder

- Count items; a folder with 100k files will be slow.
- Check for a corrupt file/thumbnail; switch to Details view.
- Move the folder to a local disk and test.
- Check permissions/offline files.

## When to reset

If clean boot and shell-extension isolation do not help, run `DISM`/`SFC`, update the GPU/chipset driver, and create a new user profile to separate profile corruption from system corruption. Reset/reinstall is the last step, not the first.

## Sources

- [Microsoft — Autoruns](https://learn.microsoft.com/en-us/sysinternals/downloads/autoruns)
- [Microsoft — Shell extensions](https://learn.microsoft.com/en-us/windows/win32/shell/shell-exts)

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Source: https://windows.homes/en/windows/fixes/explorer/