Microsoft Windows 11 24H2 Update Version OS Build 26100.9278

KB5120998 for Windows 11 24H2 (OS Build 26100.9278) adds taskbar, Start, Search, File Explorer, Windows Update, and setup improvements. It also introduces Administrator protection, Windows Autopilot device preparation GA, and updates AI components. Reference IDs: KB5120997.

• Administrator protection hardens against elevation-of-privilege attacks by using just-in-time admin privileges and profile separation.
• Windows Secure Boot certificate expiration guidance and certificate updates are highlighted for affected devices.

• Improves reliability of the taskbar system tray on non-touch PCs.
• Makes File Explorer Home faster and more responsive, and adds touch scrolling to Recommended items.
• Improves navigation and interaction in Display settings and persistence of brightness settings after energy saver turns off.
• Improves Task Manager reliability when showing app history.
• Improves restart behavior so manually sleeping PCs return to sleep after updates.
• Improves VPN-related background process resiliency and recovery.
• Improves Japanese IME typing reliability and voice typing setting persistence.
• Improves netsh wlan show wlanreport output for Japanese users.
• Improves smoother and more responsive virtual desktop switching.

• Taskbar can now be positioned on the top, left, or right side of the screen, and a smaller taskbar size option is available.
• Start menu adds small and large size options, renames Recommended to Recent, and can hide 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 adds easier secondary keyboard selection and new Get Started 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 adds Process Isolation for responsive workloads.
• Agentic process tagging preview is introduced for authorized components.
• Post-Quantum Cryptography ML-KEM can now be used as a standalone TLS key exchange algorithm.

• Administrator protection is off by default and can be enabled using OMA-URI in Microsoft Intune or through Group Policy.
• WMIC is removed starting in August 2026 for Windows 11 24H2 and 25H2 and is no longer available as a Feature on Demand; WMI remains supported.
• This update includes SSU KB5120997 (Build 26100.9270) to improve update installation reliability.
• AI components are updated to version 1.2608.951.0.

Product Information

Vendor: Microsoft

Product: Windows 11

Product type: Software

Application category: Utilities

Platform: Windows

Variant: 24H2

Version: OS Build 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.