Windows C Drive Cleanup

Windows C Drive Cleanup

Core Rules

Prefer inspection before deletion. Treat C drive cleanup as a filesystem safety task, not a generic "delete large files" task.

• State the boundary before acting: "read-only check", "cache cleanup", or "migration with junction".
• Exclude reparse points/junctions from size calculations unless explicitly verifying them.
• Never delete or move system, driver, Office, runtime, service, or uninstall-support folders just because they are large.
• Do not directly cut-and-paste app data folders. Move data to the target drive, then create a junction at the original path.
• Record every destructive or path-changing action in a timestamped folder under the current workspace.
• If deletion fails because files are in use, leave them and report that they are live temp files.
• If permission fails and the user asked for it, open the folder with Explorer instead of escalating.

Standard Workflow

1. Inspect C drive usage.

   • Measure the relevant roots with reparse points skipped.
   • Check app install registry entries and start-menu shortcuts when the user asks why an app appears on C.
   • Check running processes before touching app data.

2. Classify each large item.

   • Delete only obvious cache/temp/log/crash/update artifacts.
   • Migrate live user data that an app expects at a fixed C path.
   • Keep system components, drivers, runtimes, uninstallers, services, and account/chat databases unless the user explicitly accepts the risk.

3. Execute narrowly.

   • Close or verify absence of processes for the target app.
   • Clean small disposable targets first.
   • Migrate large live directories one at a time to the app's install drive or the user's chosen drive.
   • Create a junction from the original C path to the new location.

4. Verify.

   • Confirm original paths exist as Directory, ReparsePoint.
   • Confirm targets exist and sizes/file counts are plausible.
   • Re-check C drive free space.
   • Summarize exactly what was deleted, migrated, skipped, and why.

Useful Scripts

Use these scripts when they fit the task; read or adapt them if the exact safety policy needs adjustment.

• scripts/scan_hotspots.ps1: scan top-level C drive hotspots while skipping junction contents.
• scripts/migrate_to_junction.ps1: move one or more directories and create junctions at the original paths.
• scripts/clear_cache_targets.ps1: clear explicitly named cache/temp directories or files, skipping reparse points and recording failures.

Run scripts from PowerShell. Example:

powershell -ExecutionPolicy Bypass -File "$HOME\.codex\skills\windows-c-drive-cleanup\scripts\scan_hotspots.ps1" -Top 50

App Pattern Reference

Read references/app-patterns.md before making app-specific decisions. It captures common patterns from prior cleanup work, including Tencent/WeChat/QQ, DingTalk, Baidu Netdisk, Tencent Meeting, CloudMusic, and small generic caches.

Decision Guidance

Delete when:

• The directory name is clearly Cache, Code Cache, GPUCache, DawnCache, Temp, CrashDumps, Log, logs, update, or an old app temp folder.
• The app is closed.
• The path is under the specific app data root being handled.
• The target is not a reparse point.

Migrate when:

• The directory is large and belongs to active app state under AppData\Roaming or AppData\Local.
• The app likely recreates the same C path if the directory is merely moved.
• The user wants C space back without losing app state.

Keep when:

• The path is Program Files, Program Files (x86), ProgramData, Office, Visual C++ runtime, Edge WebView, NVIDIA, Lenovo, Autodesk, dotnet, Windows, or a service executable, unless there is a precise app-specific reason.
• The directory contains chat history, account databases, playlists, offline music, or user project data and no migration is requested.

Migration Pattern

Use a junction, not a symlink, for ordinary app data folders:

1. Verify the app is closed.
2. Verify the destination does not already exist.
3. Measure source size and file count.
4. Move source to target drive.
5. Create a junction at the original source path.
6. Verify Get-Item shows Directory, ReparsePoint and the target path is correct.

Prefer destinations near the app install directory:

• E:\Program Files (x86)\Tencent\UserData\Roaming\<name>
• E:\Program Files (x86)\DingDing\UserData\...
• E:\BaiduNetdiskDownload\BaiduNetdisk\BaiduNetdisk\UserData\...
• <non-C-drive>\TencentMeeting\UserData\...

Reporting

Keep the final answer short and concrete:

• What changed.
• What was deleted versus migrated.
• How much space was freed or moved off C.
• Which paths are now junctions.
• Any files left because they were in use or permission-protected.
• The absolute path to the timestamped record directory.