Windows 11 Update KB5074109 A Critical Look at the January 2026 Release
The January 2026 cumulative update for Windows 11, identified as KB5074109, presents a significant dilemma for users. While it delivers crucial security patches and battery life improvements, it also introduces serious bugs that can disrupt professional workflows and impact gaming performance. This analysis covers the key changes to help you decide whether to install it.
Key Improvements in Update KB5074109
This strategic update targets Windows 11 versions 24H2 and 25H2, focusing on security, efficiency, and usability.
- Massive Security Patch: The most significant benefit is the closure of 114 security vulnerabilities, making it a critical update for system safety.
- Enhanced Battery Life for NPU Devices: A major flaw causing Neural Processing Units (NPUs) to remain active during idle states has been fixed. This results in a noticeable improvement in battery life for modern laptops equipped with NPUs.
- File Explorer Upgrades: The File Explorer homepage now includes a "Recommended" section that intelligently suggests frequently used or downloaded files. This feature requires a Microsoft account to function effectively. The Dark Mode has also been improved for better consistency.
- Expanded QR Code Sharing: The ability to share via QR code has been extended beyond Wi-Fi. Users can now instantly generate QR codes for website links and cloud files directly from the share window. Mobile Hotspot functionality also gets its own QR code for easy connections.
- Usability Tweaks: The Start Menu is now smarter, featuring a new account manager and the ability to drag and drop apps directly to the taskbar.
Warning Critical Issues and Reported Bugs
Despite the improvements, this update has caused severe problems for specific user groups.
- Azure Virtual Desktop (AVD) Failure: This is the most critical issue. Users report a fatal authentication failure with error code 0x8008005 when trying to connect via AVD. This completely halts workflows for professionals who rely on this service. The only current workaround is to uninstall the update.
- Gaming Performance Drops: Numerous users 1 2, particularly those with NVIDIA graphics cards, have reported a significant drop in gaming performance, with frame rates decreasing by approximately 20 FPS after installation.
- USB Formatting Bug: A strange issue has emerged where Windows may fail to format USB flash drives with the FAT32 file system.
Should You Install This Update
The decision to install KB5074109 depends entirely on your usage profile.
- For General Users: If you are a standard home user primarily concerned with security, installing this update is highly recommended. The patching of 114 vulnerabilities outweighs the potential risks that are unlikely to affect you.
- For Professionals and Gamers: If your work depends on Azure Virtual Desktop, remote servers, or if you are a serious gamer, it is strongly advised to AVOID this update for now. Wait until Microsoft releases a subsequent patch to fix these critical bugs.
System Build Number Changes
After installation, the OS build number will change as follows:
- Version 24H2: Becomes build 26100.7623
- Version 25H2: Becomes build 26200.7623
