- The January 2026 Security Update KB5074109 for Windows 11 introduced multiple critical regressions despite being a security-only release.
- Emergency Out-of-band updates KB5077744 and KB5078127 fixed some, but not all, reported problems.
- Community reports revealed deeper instability, including graphics problems, boot failures, and broken system tools.
The January 2026 Security Update for Windows 11 was expected to be routine. No new features, no visible changes, just the usual monthly security fixes. Instead, the quality update KB5074109 (build 26200.7623) quickly turned into one of the most problematic updates in recent months.
Released on January 13, 2026, the update began generating complaints almost immediately. What followed was a growing list of confirmed bugs, user reports, and official acknowledgements that ultimately pushed many users to uninstall the update entirely.
Microsoft confirms multiple issues in KB5074109
One known issue involved Remote Desktop sign-in failures, where users were repeatedly prompted for credentials but could not authenticate. This issue directly affected Azure Virtual Desktop (AVD) and Windows 365, causing significant disruption for enterprises and remote workers.
Another confirmed bug caused applications to freeze or become unresponsive when saving files directly to cloud storage, including OneDrive and Dropbox. For users who rely on cloud-first workflows, this turned routine file operations into a frustrating experience.
Microsoft also acknowledged a serious issue affecting classic Outlook profiles using POP accounts and PST files. After installing KB5074109, Outlook could freeze, fail to open entirely, or hang silently in the background.
In this case, they went further and recommended uninstalling the update as one of the workarounds.
Microsoft noted these issues on its support page. As of the time of this writing, these issues have been fixed through the Out-of-band updates KB5077744 and KB5078127.
Community feedback exposes issues beyond Microsoft’s list
Beyond the officially known issues, user reports painted an even more troubling picture with the January 2026 Security Update.
A small number of users on Reddit and Microsoft forums reported black screens and severe frame drops, particularly on systems using NVIDIA graphics cards.
Others experienced boot failures or unresponsive systems during startup, with computers freezing before reaching the desktop. In some cases, systems only returned to normal after uninstalling the update.
On Reddit, one user described severe system instability, including frequent browser crashes and thousands of critical errors logged in Event Viewer. That same post included detailed steps for removing the update, after which system stability was reportedly restored.
Even more concerning were reports of unexpected reboots and Black Screen of Death errors, sometimes triggered by the graphics card workloads and sometimes occurring during normal startup. Once again, uninstalling KB5074109 appeared to resolve the issue.
The update also broke core components in the operating system. Some users reported that File Explorer ignored customization settings defined in desktop.ini, breaking folder views and visual preferences.
Others noticed that Task Manager would freeze or hang when certain applications were open, making it difficult to diagnose performance issues or terminate misbehaving processes.
In addition, there have been reports from built-in apps such as Notepad and Snipping Tool that refused to launch, displaying error 0x803F8001. Users also reported that Windows 11 could no longer format USB flash drives using the FAT32 file system, a basic function that should never break in a security update.
Error 0x800F0905 complicates the uninstall of the update
Ironically, even removing the update became a challenge for some users. Attempts to uninstall KB5074109 failed with error 0x800F0905, leaving affected systems stuck in a broken state.
In those cases, users were forced to rely on System Restore using a previous restore point or to restore the system from a full backup to regain stability, as their only way to remove the update.
Whether these issues affect a small percentage of systems or represent a broader quality failure is difficult to determine. What is clear is that KB5074109 generated an unusually high volume of complaints across Microsoft’s own forums, Reddit, and social media, many of which were resolved only by uninstalling the update.
If you have not installed the January 2026 Security Update yet, the safest approach is to pause updates and wait until the company permanently fixes these problems.
Personally, I prefer to disable automatic updates and install them manually once it’s clear they are safe and stable. This update is a reminder of why that approach still makes sense.
Have you experienced issues with KB5074109 on your system? Let me know in the comments.
Mauro Huculak is a Windows How-To Expert and founder of Pureinfotech in 2010. With over 22 years as a technology writer and IT Specialist, Mauro specializes in Windows, software, and cross-platform systems such as Linux, Android, and macOS.
Certifications: Microsoft Certified Solutions Associate (MCSA), Cisco Certified Network Professional (CCNP), VMware Certified Professional (VCP), and CompTIA A+ and Network+.
Mauro is a recognized Microsoft MVP and has also been a long-time contributor to Windows Central.
You can follow him on YouTube, Threads, BlueSky, X (Twitter), LinkedIn and About.me. Email him at [email protected].