Quick fix: Download the Windows 11 ISO from microsoft.com/software-download/windows11. Mount the ISO (double-click). Run setup.exe. Choose Upgrade: Install Windows and keep files, settings, and apps. This is an in-place upgrade — reinstalls Windows over itself preserving everything.

You want to refresh Windows 11 because of corruption, weird behavior, or update failures. But you want to keep all your apps, settings, and files. Reset This PC has options for this, but the in-place upgrade from ISO is often more reliable.

Symptom: Need to reinstall Windows 11 to fix corruption without losing personal files, apps, or settings.
Affects: Windows 11 (and Windows 10).
Fix time: ~1–2 hours.

What causes this

In-place upgrade replaces Windows’s system files (Windows folder, Program Files structure) with fresh copies from the ISO. Your user profile, installed apps, and registry survive. It’s like a Windows reset but more thorough — even fixes corruption that Reset This PC can’t handle.

Use cases: Windows Update keeps failing, file corruption that sfc/DISM can’t repair, system feels broken but you want to avoid full reset.

Method 1: In-place upgrade via Windows 11 ISO

The recommended route.

Visit microsoft.com/software-download/windows11.
Under Download Windows 11 Disk Image (ISO), pick edition (Windows 11), click Download. Pick language.
Save the ISO (about 5 GB) to Downloads.
Right-click the ISO → Mount. A virtual drive appears in File Explorer (typically D: or E:).
Open the mounted drive. Run setup.exe.
Setup starts. Skip downloading updates (faster).
Accept license. Wait for “Getting things ready.”
At Ready to install screen, click Change what to keep. Pick Keep personal files and apps.
Click Install. Process takes 30–90 minutes depending on PC speed.
PC reboots multiple times. Don’t interrupt.
After completion: sign in. Verify files, apps, settings all preserved.

This is the canonical refresh.

Method 2: Reset This PC with Cloud download

An alternative built into Settings.

Open Settings → System → Recovery → Reset this PC.
Click Reset PC.
Choose Keep my files (apps will be removed) OR Reset and keep your apps if available (may be Windows 11 22H2+ only).
Choose Cloud download — fresh OS from Microsoft, more reliable than Local reinstall.
On the Apps to be removed page: review. Note which apps you’ll need to reinstall.
Click Reset. Process: 30–60 minutes.
Caveat: standard Reset removes installed Win32 apps. Method 1 (in-place upgrade) preserves apps. Use Reset only if app preservation isn’t critical.

This is the GUI option. Less thorough than in-place upgrade but easier.

Method 3: Create a USB installer for offline reinstall

For when Windows won’t boot or update.

From a working PC: visit microsoft.com/software-download/windows11.
Download the Media Creation Tool. Run it. Choose Create installation media for another PC.
Pick edition, language, architecture. Save to USB drive (8+ GB).
Boot the problem PC from the USB. Press F12/F11 at boot to pick USB.
From the Windows install screen, click Install now.
Enter product key or skip (Windows is already activated; just refreshing).
Accept license. At install screen: choose Upgrade: Install Windows and keep files, settings, and apps. (Available only when running setup from within Windows.)
For from-bootable-USB: only Custom: Install Windows only (advanced) available — this is a clean install. Use Method 1 if running setup from Windows preserves data.
For unbootable Windows: boot USB, choose Repair your computer first, try Startup Repair before considering clean install.

This is the right path for severely broken Windows.

How to verify the fix worked

After upgrade: Settings → System → About. Windows version shows current (e.g., Windows 11 23H2).
All apps in Start menu launch normally.
Documents, Pictures, Downloads all intact.
Settings → About shows Installed on: today’s date for the new install.
Run winver for version confirmation.

If none of these work

If upgrade fails: Disk space: need 20+ GB free on C:. Run Disk Cleanup first. Pending Windows Updates: install all available updates before in-place upgrade. Antivirus interfering: temporarily disable third-party AV during upgrade. Re-enable after. For corrupted setup: re-download the ISO. Use a different download for re-attempt. For BitLocker-encrypted drives: suspend BitLocker before upgrade. Settings → System → Storage → Advanced storage settings → Drives where Windows is installed → BitLocker → Suspend. For PCs with unsupported hardware: official Windows 11 setup checks TPM 2.0 and CPU compatibility. If unsupported, follow the unofficial bypass (registry edits during setup). For repeated failures: collect setup logs from C:\$WINDOWS.~BT\Sources\Panther\setupact.log. Search log for first error.

Bottom line: Download Windows 11 ISO, mount, run setup.exe, choose Keep personal files and apps. In-place upgrade refreshes Windows while preserving everything. Used by Microsoft Support as primary repair tool.