# win-registry-safety

> Windows registry operation safety guidelines for context menu editing. Use when modifying, adding, or deleting registry keys under HKCR (HKEY_CLASSES_ROOT), implementing enable/disable toggles, or working with shell/shellex entries. Triggers on: any code that calls Registry.ClassesRoot, CreateSubKey, DeleteSubKeyTree, or modifies context menu registry paths.

- Author: graffetta
- Repository: enraku/WinContextMenuEditor
- Version: 20260129064144
- Stars: 0
- Forks: 0
- Last Updated: 2026-02-06
- Source: https://github.com/enraku/WinContextMenuEditor
- Web: https://mule.run/skillshub/@@enraku/WinContextMenuEditor~win-registry-safety:20260129064144

---

---
name: win-registry-safety
description: "Windows registry operation safety guidelines for context menu editing. Use when modifying, adding, or deleting registry keys under HKCR (HKEY_CLASSES_ROOT), implementing enable/disable toggles, or working with shell/shellex entries. Triggers on: any code that calls Registry.ClassesRoot, CreateSubKey, DeleteSubKeyTree, or modifies context menu registry paths."
---

# Registry Safety Guidelines

## Critical Rules

1. **Never delete without confirmation** - always show a confirmation dialog before `DeleteSubKeyTree`
2. **ShellEx warnings** - when deleting shellex entries, warn that third-party app functionality may break
3. **Backup before bulk changes** - export to .reg before batch operations
4. **Use writable:true explicitly** - `OpenSubKey(path, writable: true)` - never assume write access
5. **Catch and handle SecurityException** - HKCR writes require admin; gracefully handle permission denied

## Registry Paths

| Category | Shell | ShellEx |
|---|---|---|
| All Files | `*\shell` | `*\shellex\ContextMenuHandlers` |
| Directory | `Directory\shell` | `Directory\shellex\ContextMenuHandlers` |
| Dir Background | `Directory\Background\shell` | `Directory\Background\shellex\ContextMenuHandlers` |
| Desktop Background | `DesktopBackground\shell` | `DesktopBackground\shellex\ContextMenuHandlers` |
| Drive | `Drive\shell` | `Drive\shellex\ContextMenuHandlers` |
| Extension | `.ext` -> ProgID -> `{ProgID}\shell` | `{ProgID}\shellex\ContextMenuHandlers` |

## Enable/Disable Patterns

- **Shell items**: set `LegacyDisable` (REG_SZ, empty) to disable; delete value to enable
- **ShellEx items**: rename key with `-` prefix to disable (e.g., `MyHandler` -> `-MyHandler`); preserve default value (CLSID) during rename

## Win11 Classic Menu

- CLSID: `{86ca1aa0-34aa-4e8b-a509-50c905bae2a2}`
- Force classic: create `HKCU\Software\Classes\CLSID\{...}\InprocServer32` with empty default value
- Revert: delete the CLSID subtree under HKCU
- Requires Explorer restart to take effect

## Safe Coding Patterns

```csharp
// Always use 'using' for registry keys
using var key = Registry.ClassesRoot.OpenSubKey(path, writable: true);
if (key == null) return; // guard against missing keys

// Delete values safely
key.DeleteValue("ValueName", throwOnMissingValue: false);

// Delete subkeys safely
parentKey.DeleteSubKeyTree(keyName, throwOnMissingSubKey: false);
```

For detailed registry path reference, see [references/registry-paths.md](references/registry-paths.md).