By skyforbes 
This update address Local Security Authority Subsystem Service (LSASS) bug that led to high CPU usage and system instability
Microsoft has rolled out KB5063878 update for Windows 11 version 24H2. This is part of August 2025’s Patch Tuesday release advance to windows 11 build 26100.4946 and focuses on security patch. It also introduces the new Quick Machine Recovery feature, a modernized Black Screen of Death, and enhanced AI capabilities for Copilot+ PCs.
This update introduced new Quick Machine Recovery feature, designed to help users recover from severe system failures without losing personal data.
Quick Machine Recovery allows users to restore Windows from within Advanced Startup or when stuck in a boot loop, using built-in recovery tools without requiring external media.
It’s enabled by default for home users and can be managed under System > Recovery > Quick machine recovery.
The update also includes several AI-driven enhancements, particularly for Copilot+ PCs that meet the 40+ TOPS NPU requirement.
The Settings app now features a redesigned, top-centered search bar that doubles as an AI assistant on supported devices. Users can type natural language queries like “How do I extend battery life?” and receive intelligent suggestions tailored to their system configuration.
Additionally, the Recall feature, which allows users to search through their device activity history, is now officially available in the European Economic Area (EEA), with improved privacy controls to comply with GDPR regulations.
Windows 11 KB5063878 introduces a new Black Screen of Death (BSoD) to replace the traditional Blue Screen of Death error. It also includes a QR code that directs users to Microsoft support resources help fix the error.
The update also includes patches for 111 vulnerabilities, including one zero-day (CVE-2025–53779) and 13 critical flaws related to privilege escalation and remote code execution.
Additionally, the update address a problems with the Local Security Authority Subsystem Service (LSASS), which had led to high CPU usage and system instability, as well as crashes in the Settings app when saving Wi-Fi credentials.
To Download and install Windows 11 KB5063878, you can do so through the standard Windows Update process. Open Settings > Windows Update and click Check for updates. If the update is available, it will appear as “2025–08 cumulative update for windows 11 version 24h2 for x64-based systems” and can be downloaded and installed automatically. A system restart is required to complete the installation and apply changes.
Also the update can be downloaded directly from the Microsoft Update Catalog (https://www.catalog.update.microsoft.com) by searching for KB5063878 and selecting the appropriate package for your system architecture (x64 or ARM64).
It can be also deployed via management tools like Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager.
Microsoft recommends installing this update immediately to get benefit from critical security fixes, performance improvements and new features.
If you experience problem installing this update, Windows 11 24h2 update kb5063878 fails try solutions suggested following video.
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