Windows-Preflight-Cleaner

🇫🇷 Version française

Self-contained PowerShell maintenance script for Windows 11. Safely cleans 46+ system/app caches, logs, temp files and WinSxS via DISM, flushes DNS, empties Recycle Bin. Ships with dry-run mode, 17-check self-test, exit codes and HTML/JSON reports for multi-machine deployment.

No blind deletes, ever. A path safety guard rejects unsafe paths, dry-run previews exactly what would happen first, and locked files are reported honestly instead of silently skipped.

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Table of contents

• Overview
• What it cleans
• What it does NOT touch
• Prerequisites
• First run
• Parameters
• Exit codes
• Generated reports
• Multi-machine deployment
• Troubleshooting

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Overview

Nettoyage-Windows11-v5_2.ps1 cleans system and application caches, obsolete logs, multi-user temporary files, and Windows components (WinSxS via DISM) on a Windows 11 machine.

On every run, it:

• processes 46 fixed cleanup targets, grouped into categories (plus dynamic targets: detected LibreWolf profiles, other Windows accounts present on the machine);
• flushes the DNS cache and empties the Recycle Bin;
• runs a Windows component cleanup via DISM (StartComponentCleanup, with an optional /ResetBase);
• generates an HTML report (dark dashboard theme), a full JSON export, a CSV history export, and a JSON baseline used to compute a delta against the previous run;
• automatically purges old reports past a configurable retention period.

Designed to run both interactively (workstation) and silently (scheduled task, multi-machine deployment).

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What it cleans

Windows Update

Target	Path
Windows Update	C:\Windows\SoftwareDistribution\Download

wuauserv is stopped for the duration of the cleanup, then restarted.

Temporary files and system caches

Target	Path
User Temp	%TEMP%
Windows Temp	C:\Windows\Temp
DirectX Cache	%LOCALAPPDATA%\D3DSCache
Delivery Optimization	C:\Windows\SoftwareDistribution\DeliveryOptimization
Explorer Thumbnails	%LOCALAPPDATA%\Microsoft\Windows\Explorer
WER ReportArchive	C:\ProgramData\Microsoft\Windows\WER\ReportArchive
WER ReportQueue	C:\ProgramData\Microsoft\Windows\WER\ReportQueue
WER Temp	%LOCALAPPDATA%\Microsoft\Windows\WER\Temp
CrashDumps	%LOCALAPPDATA%\CrashDumps

Logs

Target	Path
WindowsUpdate Logs	C:\Windows\Logs\WindowsUpdate
CBS Logs	C:\Windows\Logs\CBS
DISM Logs	C:\Windows\Logs\DISM
Panther Setup Logs	C:\Windows\Panther

Prefetch and memory dumps

Target	Path
Prefetch	C:\Windows\Prefetch
Memory Dumps (Minidump)	C:\Windows\Minidump
MEMORY.DMP	C:\Windows\MEMORY.DMP

Unit system caches

Target	Path
IconCache.db	%LOCALAPPDATA%\IconCache.db
FNTCACHE.DAT	C:\Windows\System32\FNTCACHE.DAT

FontCache service is stopped for the duration of the cleanup, then restarted.

Developer tools

Target	Path
npm cache	%APPDATA%\npm-cache
pip cache	%LOCALAPPDATA%\pip\Cache
cargo cache	%USERPROFILE%\.cargo\registry\cache
VS Code Cache	%APPDATA%\Code\Cache
VS Code CachedData	%APPDATA%\Code\CachedData
VS Code Logs	%APPDATA%\Code\logs
VS Code GPUCache	%APPDATA%\Code\GPUCache

WebView2

Chromium component independent from Edge, used by Widgets, Teams, and various apps for embedded web rendering — cache only, regenerates automatically, no risk.

Target	Path
WebView2 Cache	%LOCALAPPDATA%\Microsoft\EdgeWebView\User Data\Default\Cache
WebView2 Code Cache	%LOCALAPPDATA%\Microsoft\EdgeWebView\User Data\Default\Code Cache
WebView2 GPUCache	%LOCALAPPDATA%\Microsoft\EdgeWebView\User Data\Default\GPUCache

Recent access history

Start Menu / Taskbar JumpLists — purely cosmetic/privacy-related, automatically rebuilt through normal use.

Target	Path
Automatic JumpLists	%APPDATA%\Microsoft\Windows\Recent\AutomaticDestinations
Manual JumpLists	%APPDATA%\Microsoft\Windows\Recent\CustomDestinations

NVIDIA

Target	Path
NVIDIA DXCache	%LOCALAPPDATA%\NVIDIA\DXCache
NVIDIA GLCache	%LOCALAPPDATA%\NVIDIA\GLCache
NVIDIA OptixCache	%LOCALAPPDATA%\NVIDIA\OptixCache

Spotify

Target	Path
Spotify Storage Cache	%LOCALAPPDATA%\Spotify\Storage
Spotify Data Cache	%LOCALAPPDATA%\Spotify\Data

Steam (conditional — only if detected via HKCU:\Software\Valve\Steam)

Target	Path
Steam AppCache	<Steam folder>\appcache
Steam HtmlCache	<Steam folder>\htmlcache
Steam incomplete downloads	<Steam folder>\steamapps\downloading

Browsers

Target	Path
Brave Cache	%LOCALAPPDATA%\BraveSoftware\Brave-Browser\User Data\Default\Cache
Brave Code Cache	%LOCALAPPDATA%\BraveSoftware\Brave-Browser\User Data\Default\Code Cache
Brave GPU Cache	%LOCALAPPDATA%\BraveSoftware\Brave-Browser\User Data\Default\GPUCache
LibreWolf Cache [profile]	one Cache/StartupCache pair generated per LibreWolf profile detected automatically on the machine (0, 1, or several)
LibreWolf StartupCache [profile]	—

Multi-user temp profiles (dynamic target)

Target	Path
Temp [account_name]	C:\Users\<account>\AppData\Local\Temp for every Windows account present on the machine other than the current user

Non-target actions (run on every execution, except in -DryRun mode)

Action	Detail
DNS Cache	ipconfig /flushdns
Recycle Bin	full purge (all drives)
System Restore Point	optional, -CreateRestorePoint — subject to Windows' 1-checkpoint-per-24h throttle for MODIFY_SETTINGS
DISM StartComponentCleanup	cleans up old WinSxS component versions. With -ResetBase (separate option, requires interactive confirmation): permanently removes old component versions — no update rollback possible afterwards

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What it does NOT touch

• No documents, photos, projects, or user files — only caches, logs, and temporary files that are automatically regenerated by Windows or the relevant applications.
• No browser data other than the cache — browsing history, saved passwords, bookmarks, cookies, open sessions: all left untouched.
• The Windows registry is never modified.
• An internal safety guard (Test-SafeCleanupPath) automatically rejects any target located fewer than 2 levels below a drive root (C:\, C:\Windows, C:\Users...), to protect against a future configuration mistake that could point the cleanup at a system folder that's too broad.

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Prerequisites

• Windows 11 (also works on Windows 10, not the primary target for testing).
• PowerShell 5.1 (built into Windows) or PowerShell 7+.
• Administrator rights. The script self-elevates if launched from a non-admin session (UAC prompt).
• robocopy.exe and DISM.exe present (built into Windows by default).
• The reports folder must be writable: %USERPROFILE%\Desktop\Rapports_Maintenance\Nettoyage systeme (automatically created on first run if missing).
• If the script is digitally signed (recommended in environments using -ExecutionPolicy AllSigned/RemoteSigned): the signing certificate must be trusted on the target machine, otherwise PowerShell will refuse to run it.

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First run (step by step)

1. Copy Nettoyage-Windows11-v5_2.ps1 to the target machine (for example into a C:\Scripts\Maintenance folder).

2. Open a PowerShell terminal (no need to run it as admin manually — the script self-elevates).

3. Check system prerequisites without cleaning anything:

   .\Nettoyage-Windows11-v5_2.ps1 -SelfTest

   Runs 17 automated checks (admin rights, presence of robocopy/DISM, required services, internal script functions) and displays PASS/FAIL for each. The script exits without touching any files. Expected exit code: 0 (see Exit codes).

4. Run a full simulation before the first real cleanup, to preview what would be removed without removing anything:

   .\Nettoyage-Windows11-v5_2.ps1 -DryRun

   Calculates potential gains per target, generates an HTML report flagged [SIMULATION MODE], and performs no deletion, no DISM run, and no DNS/Recycle Bin flush.

5. Read the generated HTML report (the script offers to open it automatically, unless -Silent is used) to confirm the targets and estimated volumes make sense on this particular machine.

6. Run the first real cleanup:

   .\Nettoyage-Windows11-v5_2.ps1

   Answer the interactive prompts (open report, final ENTER confirmation). The full cleanup typically takes under 10 seconds excluding DISM (StartComponentCleanup can take several minutes depending on the state of the WinSxS folder).

7. (Optional, for automated deployment) once the behavior has been validated manually, schedule the run via Windows Task Scheduler with -Silent (see Multi-machine deployment).

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Parameters

Parameter	Description
-Silent	Suppresses interactive prompts (-ResetBase confirmation, final ENTER pause) and does not automatically open the HTML report. Use consistently for scheduled tasks.
-DryRun	Simulation mode: calculates potential gains without deleting anything, without running DISM, and without flushing DNS/Recycle Bin.
-SelfTest	Checks prerequisites and 10 internal script functions (formatting, safety guard, file lock detection, JSON/CSV round-trip, LibreWolf/Steam detection), then exits without cleaning. 17 checks total.
-CreateRestorePoint	Creates a system restore point before the DISM cleanup. Subject to Windows' 1-checkpoint-per-24h throttle for MODIFY_SETTINGS (may fail silently — normal Windows behavior, not a bug).
-ResetBase	Adds /ResetBase to the DISM cleanup: permanently removes old WinSxS component versions. No update rollback possible afterwards. Requires interactive confirmation unless -Silent is used.
-SkipTargets "Name1","Name2"	List of target names to skip (exact names as shown in the console). A typo that matches no real target triggers an explicit warning at the end of the run.
-OnlyTargets "Name1","Name2"	List of target names to process exclusively (all others skipped). Same typo detection as -SkipTargets.
-RetainReportsDays <number>	Days HTML/JSON/Transcript reports are retained before automatic purge (default: 60). CSV history and JSON baseline are never purged. Use 0 to disable the purge.

Examples:

.\Nettoyage-Windows11-v5_2.ps1 -DryRun
.\Nettoyage-Windows11-v5_2.ps1 -Silent -SkipTargets "Prefetch","Steam AppCache"
.\Nettoyage-Windows11-v5_2.ps1 -CreateRestorePoint -ResetBase
.\Nettoyage-Windows11-v5_2.ps1 -RetainReportsDays 30

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Exit codes

Useful for integrating the script into multi-machine monitoring without parsing the text transcript.

Code	Meaning
0	Full run completed, nothing to report
1	Run completed but locked/protected targets were detected (files in use during cleanup), or -SelfTest failed
2	Unhandled fatal error (caught by a global safety net that displays the error message before exiting)

Check after a run:

echo $LASTEXITCODE

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Generated reports

On every run (including -DryRun, and partially -SelfTest), the script writes to:

%USERPROFILE%\Desktop\Rapports_Maintenance\Nettoyage systeme\

File	Content
Nettoyage-YYYY-MM-DD_HH-mm-ss.html	Visual report: summary tiles, disk usage bar, 10-run trend, per-target detail with color-coded status, action log
Nettoyage-YYYY-MM-DD_HH-mm-ss.json	Full export of all run data
Transcript-YYYY-MM-DD_HH-mm-ss.log	Raw PowerShell transcript
Historique_v5.csv	Cumulative history (append-only), never purged
Baseline_v5.json	State of the last run, used to compute the delta on the next run, never purged

HTML/JSON/Transcript reports older than -RetainReportsDays (60 days by default) are purged automatically at the end of the run.

In the HTML report, each target displays a status badge:

Badge	Meaning
✅ green	Cleaned
🟡 ~	Partially cleaned (partly locked/protected)
🔴 !	Locked or protected (nothing could be removed)
⬜ -	Already empty
🟡 ≈	Simulation (-DryRun only)

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Multi-machine deployment

The script is self-contained (no external dependencies other than robocopy.exe and DISM.exe, both built into Windows).

1. Distribute the .ps1 file (network copy, GPO, deployment tool, or a clone of this repository) to a local folder on each machine.

2. Trust the signing certificate if a strict execution policy is enforced (-ExecutionPolicy AllSigned/RemoteSigned) — either "Trusted Root Certification Authorities" or "Trusted Publishers", depending on the policy in place. Otherwise PowerShell refuses to run it.

3. Run -SelfTest first on each machine to validate prerequisites before any real cleanup. The exit code makes this easy to automate.

4. Schedule via Windows Task Scheduler (or your enterprise equivalent), with -Silent mandatory to avoid getting stuck on an interactive prompt:

   Field	Value
   Program/script	pwsh.exe (or powershell.exe)
   Arguments	-NoProfile -ExecutionPolicy Bypass -File "C:\Scripts\Maintenance\Nettoyage-Windows11-v5_2.ps1" -Silent
   Run with highest privileges	Yes (required for administrator rights)

5. Monitor via $LASTEXITCODE rather than parsing the transcript: a code of 1 or 2 warrants a manual check or an alert in your monitoring tool.

6. The CSV history and JSON baseline are local to each machine (stored in the profile of the user running the script) — no data is centralized automatically. A centralized rollup (network share, JSON collection) is left to be implemented separately if a consolidated multi-machine view is needed.

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Troubleshooting

A target shows up red (!) or yellow (~) in the report

Some files were open in an application at the time of cleanup (e.g. a browser running while its cache was being cleaned). Close the relevant application and re-run the script to finish cleaning that target. The end-of-run summary lists the affected targets along with the exact amount of space that could not be recovered.

-OnlyTargets or -SkipTargets seems to do nothing

Double-check the exact target name spelling (see What it cleans, or the names shown in the console during a normal run). The script displays an explicit warning at the end of the run if a provided name matches no real target.

-SelfTest reports a FAIL

Read the label of the failing test: it generally points to a missing system prerequisite (admin rights, a stopped Windows service, robocopy/DISM missing from a restricted environment, a non-writable reports folder). Fix the prerequisite, then re-run -SelfTest.

The system restore point consistently fails

Normal Windows behavior if a checkpoint was already created within the last 24 hours for the MODIFY_SETTINGS type (Windows throttling, not a script bug).

The measured disk gain is close to 0 even though items were deleted

Normal: Windows can reclaim freed space almost instantly for its own purposes (disk cache, temporary system files generated in parallel). Refer instead to the per-target "Gain" column in the HTML report, which precisely measures the space freed for each cleaned folder.

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_{Nettoyage-Windows11 v5.2 — built and hardened through iterative real-machine testing.}