Microsoft Windows 11 25H2 Update Version OS Builds 26200.9278 and 26100.9278

KB5120998 for Windows 11 version 25H2 introduces taskbar, Start, Search, File Explorer, Windows Update, and setup improvements. It also begins rolling out Administrator protection, adds support for app update coordination with Windows Update, and includes SSU KB5120997.

• Administrator protection hardens against elevation-of-privilege attacks by using just-in-time administrative privileges and profile separation.
• Windows Secure Boot certificate expiration guidance: updated certificates continue to be delivered through Windows Update for devices that have not yet received them.

• Improves reliability of loading the system tray area on non-touch PCs.
• Improves File Explorer Home responsiveness and touch scrolling in the Recommended section.
• Improves reliability of navigating and interacting with Display settings.
• Improves persistence of brightness settings after energy saver turns off.
• Improves reliability of displaying app history in Task Manager.
• Improves restart behavior so manually sleeping PCs return to sleep after updates.
• Improves VPN-related background process resiliency to reduce hangs.
• Improves Japanese IME typing reliability and voice typing setting persistence.
• Improves netsh wlan show wlanreport output for Japanese users.

• Taskbar can now be positioned on the top, bottom, left, or right, with a smaller taskbar option.
• Start menu adds small and large size options, renames Recommended to Recent, and allows hiding the user name and profile picture.
• Windows Search adds simplified home, clearer result source labels, web and Store suggestion controls, and automatic indexing of frequently used folders.
• Windows Share can suggest and install relevant apps for work or school accounts.
• Windows Setup and Get Started add improved keyboard selection and new personalization pages.
• App updates can coordinate with Windows Update through the Windows Update Orchestration Platform.
• Microsoft Store adds support for in-app purchases in packaged WinUI 3 apps that require elevation.
• Windows Autopilot device preparation device association is now generally available.
• Microsoft Execution Containers add Process Isolation for responsive workloads.
• Agentic processes preview support tagging processes with an opaque agent identifier.
• Post-Quantum Cryptography ML-KEM can now be used as a standalone TLS key exchange algorithm.
• AI components updated to version 1.2608.951.0.

• WMIC is removed starting in August 2026 for Windows 11 versions 24H2 and 25H2 and is no longer available as a Feature on Demand; WMI remains supported.
• Administrator protection is off by default and can be enabled using OMA-URI in Microsoft Intune or through Group Policy.
• Windows 11 version 24H2 Home and Pro editions reach end of updates on October 13, 2026; Enterprise and Education remain supported until October 12, 2027.
• The update is delivered in gradual rollout and normal rollout phases, so feature availability may vary by device.

Product Information

Vendor: Microsoft

Product: Windows 11

Product type: Software

Application category: Utilities

Platform: Windows

Variant: 25H2

Version: OS Builds 26200.9278 and 26100.9278

Vendor release date: Aug 27, 2026

Original release notes: View on vendor site

Published on updatealert.io: Aug 29, 2026

Description: Client operating system for modern desktop and enterprise environments.