Windows 11 Cloud rebuild — what it does, how to start it, and what Microsoft documents (KB5127936)

This guide follows Microsoft documentation only. It includes no invented success rates, testimonials, or third-party tool promotions.

Per Microsoft Learn — Cloud rebuild (https://learn.microsoft.com/en-us/windows/configuration/cloud-rebuild/), the feature restores a Windows 11 PC to a clean, known-good state with a full OS reinstall. Unlike a classic Reset, Cloud rebuild pulls both the target image and drivers from Windows Update — including when Windows will not start (via WinRE).

When rebuild completes, the device boots into OOBE. Managed devices can re-provision through Autopilot / Intune; OneDrive cloud files are not removed by the rebuild.

- KB5127936: non-security preview, October 28, 2026.

- Builds: 26300.9818 and 26200.9818.

- Applies to (per KB): Windows 11 version 25H2 and 26H2, all editions listed on the Support page.

- The KB lists Cloud rebuild as a new recovery option (gradual rollout possible) and links to Learn.

- Learn notes that data sanitization in Cloud rebuild requires the October 2026 Windows non-security update or later for your Windows 11 version.

Typical consumer path: Settings > Windows Update > Advanced options > Optional updates (availability still depends on rollout on your device).

Before you start Cloud rebuild, Microsoft says to confirm:

- The device runs Windows 11 and has a healthy Windows Recovery Environment (check with elevated reagentc /info).

- The OEM included a compatible networking driver in WinRE, and the device can reach the internet from WinRE.

- The hardware meets Windows 11 minimum requirements.

- Go to Settings > System > Recovery.

- Select Rebuild PC next to “Rebuild this PC.”

- The device restarts into WinRE and starts Cloud rebuild.

After repeated boot failures, WinRE may open automatically. Choose Troubleshoot, then Cloud rebuild (exact menu labels can vary; the KB also mentions Recovery / uninstall paths depending on build).

Cloud rebuild needs internet access. Ethernet usually connects automatically; for Wi‑Fi, Learn says to pick a WPA-Personal network and enter the passkey. The KB also notes WinRE can reuse eligible saved Wi‑Fi profiles (rolling out).

After network prep, choose how thoroughly files are removed before Windows is reinstalled:

- Remove files — use if you plan to keep the PC. Faster; Microsoft notes files might still be recoverable with specialized tools.

- Remove & sanitize files — use before recycling, returning, or reassigning the PC. May take longer. On multi-disk PCs you can sanitize the Windows disk only or all disks.

Microsoft warning: sanitization is irreversible. Cloud rebuild reformats the system disk and removes locally stored files, accounts, apps, and settings. Data in cloud services such as OneDrive is not affected.

Keep the device plugged into power. Do not power off or manually restart during preparation, download, install, or sanitization — interrupting the process can leave Windows unable to boot.

Learn also states sanitization depends on the storage hardware (Windows requests erase and reports the device’s result). For policy or regulatory retirement, confirm support with the manufacturer.

KB5127936 also addresses (non-exhaustive; see Support):

- Remote Desktop failures with error 0xC000000D in some Administrator protection scenarios.

- Smart App Control toggle grayed out after it was turned off — fixed.

- Always On VPN connection issues after the September security update.

In KB5127936 known issues, Microsoft states that after the September 8, 2026 security update, some USB Audio Class 1.0 devices may show “This device cannot start (Code 10),” no audio output, unresponsive volume, etc. Microsoft is still working on a resolution; this preview does not claim to fix it. See also Windows release health — 26H2 (https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-26H2).

- No success percentages, lab benchmarks, or fabricated user stories.

- Cloud rebuild is not a catch-all fix for every audio, driver, or gaming issue: it is a full reinstall that deletes local data.

- No commercial third-party tool promotion.

- Microsoft Learn — Cloud rebuild (https://learn.microsoft.com/en-us/windows/configuration/cloud-rebuild/)

- KB5127936 — October 28, 2026 (builds 26300.9818 / 26200.9818) (https://support.microsoft.com/en-us/servicing/os/windows-11/2026/10/kb5127936-windows-11-25h2-26h2-update)

- Windows 11 version 26H2 — release health (https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-26H2)

Microsoft documentation only. Consulted: November 5, 2026, Europe/Paris.