Windows 11 Update KB5074109: Critical Security Fixes and Bug Alerts

The January 2026 cumulative update for Windows 11, known as KB5074109, delivers essential security enhancements and system improvements but arrives with significant bugs that may affect specific users. This release presents a complex choice, balancing critical vulnerability fixes against potential disruptions to professional and gaming activities. Understanding the full scope of its changes is key to making an informed installation decision.

This strategic update applies to Windows 11 versions 24H2 and 25H2, focusing on three core areas: security, efficiency, and user experience.

A primary advantage is the inclusion of a massive security patch addressing 114 distinct vulnerabilities. This makes the update a vital consideration for maintaining system integrity and protecting against potential threats. For devices with modern hardware, a notable efficiency gain has been introduced. The update corrects a flaw that prevented Neural Processing Units (NPUs) from entering a low-power idle state. This fix leads to a measurable improvement in battery life for laptops equipped with these specialized processors.

User interface refinements are also part of the package. The File Explorer homepage now features a “Recommended” section, which uses intelligence to surface frequently accessed or recently downloaded files. It is important to note that utilizing this smart feature requires signing in with a Microsoft account. Visual consistency receives a boost as well, with further polish applied to the system’s Dark Mode. Sharing content becomes more versatile with an expansion of QR code functionality. Beyond just Wi-Fi credentials, users can now generate QR codes directly from the share window for website links and files stored in the cloud. Even the Mobile Hotspot feature benefits, gaining its own scannable code for simpler device connections. Additional usability tweaks include a more intelligent Start Menu, complete with a new account manager and the convenient ability to drag applications directly onto the taskbar for pinning.

Despite these valuable improvements, the update has triggered several serious problems that impact particular workflows.

The most severe issue reported involves Azure Virtual Desktop (AVD). Professionals relying on this service have encountered a fatal authentication failure, signaled by error code 0x8008005, which completely blocks connection attempts. For these users, the only known solution at present is to remove the update entirely. Another widespread complaint concerns gaming performance. Multiple reports, especially from users with NVIDIA graphics cards, indicate a substantial drop in frame rates after installing KB5074109, with decreases averaging around 20 FPS in many titles. A more obscure but frustrating bug has also surfaced, where the operating system sometimes fails to format USB flash drives using the FAT32 file system.

Determining whether to proceed with this update hinges on your primary computer use.

For the average home user whose main priority is security, applying KB5074109 is highly recommended. The benefit of closing over a hundred security holes generally outweighs the risk of encountering the specific bugs, which are less likely to affect casual usage. However, a different approach is warranted for other groups. If your profession depends on Azure Virtual Desktop or remote server access, you should avoid installing this update for the time being. The same caution applies to serious gamers who cannot afford a hit to their system’s performance. The prudent course is to wait for Microsoft to issue a follow-up patch that resolves these critical issues.

Following a successful installation, the operating system’s build number will advance. For Windows 11 24H2, the new build becomes 26100.3000, while Windows 11 25H2 updates to build 26200.3000.

(Source: TechNetBook)