KB5124008: Overview with user sentiment and feedback

Overview

KB5124008 is a September 8, 2026 cumulative security update for Windows 11 versions 24H2 and 25H2 (OS Builds 26200.9445 and 26100.9445). This update provides security improvements, Secure Boot certificate deployment enhancements, and targeted bug fixes for personalization, input devices, and remote connectivity features. The update includes a servicing stack update (KB5124007) to improve Windows update installation reliability.

General Purpose

• Security updates addressing multiple vulnerabilities and providing protections against latest threats
• Secure Boot certificate deployment expansion with improved device targeting data for automatic certificate updates
• Mouse cursor customization fix restoring proper display of pointer styles and colors
• Desktop background and personalization settings loading correction addressing black desktop issues
• Teams and Outlook stability improvements for ARM64-based PCs preventing unexpected application closures
• Remote Desktop audio redirection fixes for proper audio playback in remote sessions
• Morocco Standard Time adjustment reflecting permanent UTC+00:00 transition effective September 20, 2026

General Sentiment

Community reception has been mixed following this update's release. While Microsoft reports no known issues officially, multiple users across Reddit and Microsoft Community forums have reported significant File History functionality failures after installation. Users describe the feature becoming completely non-functional with backup operations ceasing and previous version restoration unavailable. Some users also report VM folder sharing breakage and boot integrity issues with related .NET Framework updates. However, the update does address previously identified issues with Teams/Outlook crashes on ARM64 systems and personalization settings, which received positive acknowledgment from affected users.

Known Issues

• File History feature stops working completely after installation, with backup operations failing to execute and "No previous version available" messages appearing for new files
• File History panel displays "InconsistentState" errors and prompts for hard drive connection despite drives being properly connected and functional
• VM folder sharing functionality reported as broken with no error messages displayed
• Related KB5126052 (.NET Framework update) causing boot failures with Code Integrity errors on some systems, requiring BitLocker disablement via WinRE

Disclaimer: We take measures to ensure that AI-generated content is of the highest possible quality, but we cannot guarantee its accuracy and recommend that users do their own independent research. Generated on 2026-09-11 07:11 AM

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