Microsoft released the Windows 11 KB5074109 cumulative security update on January 13, 2026. It applies to Windows 11 versions 24H2 and 25H2 and includes security patches, battery-efficiency improvements, networking fixes, Secure Boot changes and reliability updates.
KB5074109 also introduced several known issues affecting cloud-based file storage, Outlook, Azure Virtual Desktop and Windows 365. These problems were subsequently addressed through later Windows updates.
This guide explains what KB5074109 changed, which Windows builds it updated, the current status of its known issues and what you should do if the update is still listed on your PC.
Quick Answer: What Is KB5074109?
KB5074109 is the January 2026 cumulative security update for Windows 11 versions 24H2 and 25H2. It updates Windows 11 24H2 to Build 26100.7623 and Windows 11 25H2 to Build 26200.7623.
- Release date: January 13, 2026
- Windows 11 24H2 build: 26100.7623
- Windows 11 25H2 build: 26200.7623
- Update type: Mandatory cumulative security update
- Major improvements: Security, NPU power usage, networking, Secure Boot and system reliability
- Known issues: Remote desktop authentication and cloud-storage file problems, both subsequently resolved
If you are updating Windows today, install the newest cumulative update offered through Windows Update instead of manually installing this older January 2026 package. Later cumulative updates include previous security fixes and improvements.
Windows 11 KB5074109 Overview
| Update detail | Information |
|---|---|
| KB number | KB5074109 |
| Release date | January 13, 2026 |
| Supported versions | Windows 11 24H2 and Windows 11 25H2 |
| Windows 11 24H2 build | 26100.7623 |
| Windows 11 25H2 build | 26200.7623 |
| Processor architectures | x64 and ARM64 |
| Restart required | Normally, yes |
| Delivery method | Windows Update, Windows Update for Business, WSUS and Microsoft Update Catalog |
Because KB5074109 is cumulative, it includes security fixes and quality improvements from earlier Windows 11 updates, as well as the changes introduced in January 2026.
Users comparing versions or planning an upgrade can explore the available Windows 11 editions before choosing the most suitable option for their device.
What Does the Windows 11 KB5074109 Update Include?
1. January 2026 Security Fixes
The primary purpose of KB5074109 is to address security vulnerabilities across Windows 11. These protections cover Windows components and are one of the main reasons users should keep their systems updated.
The update also introduces security hardening that limits how certain applications can automatically enter credentials during remote-support sessions or automated authentication workflows.
Following this change, credential dialog boxes may no longer respond to virtual keyboard input generated by some remote desktop, screen-sharing or automation applications. This is an intentional security change rather than a conventional software bug.
2. Improved Battery Efficiency on NPU Devices
KB5074109 fixes an issue that could leave a device’s Neural Processing Unit powered on while the computer was idle.
An NPU is a specialised processor used to accelerate artificial intelligence tasks. Keeping it active unnecessarily could affect battery performance, particularly on newer AI-enabled laptops and Copilot+ PCs.
The update corrects this behaviour so supported devices can manage NPU power consumption more efficiently.
3. Windows Subsystem for Linux Networking Fix
The update fixes a mirrored-networking problem in Windows Subsystem for Linux. The issue could generate a “No route to host” error and prevent WSL applications from accessing business resources through a VPN, even while the main Windows system remained connected.
This improvement is particularly relevant to developers and IT professionals who use WSL in managed or enterprise environments.
4. Azure Virtual Desktop RemoteApp Fix
KB5074109 includes a fix for RemoteApp connection failures in some Azure Virtual Desktop environments. This particular problem could occur after an earlier Windows preview update.
This improvement is separate from the Windows App authentication issue that appeared after KB5074109 was installed. That later issue is covered in the known-issues section below.
5. Secure Boot Certificate Preparation
KB5074109 continues Microsoft’s staged deployment of newer Secure Boot certificates.
Windows quality updates use device-targeting information to identify eligible systems that can safely receive the new certificates. Microsoft distributes them gradually after devices demonstrate sufficient successful update signals.
The process helps Windows devices maintain Secure Boot protection and compatibility with Microsoft’s updated certificate infrastructure.
6. Older Modem Drivers Removed
The update removes several outdated modem drivers:
- agrsm64.sys
- agrsm.sys
- smserl64.sys
- smserial.sys
Legacy modem hardware that depends specifically on these drivers may stop working after the update. Most modern Windows 11 computers do not use this older hardware.
7. Windows Deployment Services Behaviour Change
KB5074109 changes the default behaviour of Windows Deployment Services. WDS no longer supports certain hands-free deployment functions by default.
This change mainly affects IT administrators who use automated deployment workflows. Home users are unlikely to notice any difference.
8. WinSqlite3.dll Security Update
Microsoft updated the Windows WinSqlite3.dll component after some security applications identified the previous version as potentially vulnerable.
WinSqlite3.dll is a Windows component and is separate from sqlite3.dll files that may be installed inside individual application folders.
Windows 11 KB5074109 Known Issues and Current Status
The two most significant issues directly associated with KB5074109 have been resolved through subsequent Windows updates.
Azure Virtual Desktop and Windows 365 Authentication Failures
After KB5074109 was installed, some users experienced credential-prompt failures when establishing remote desktop connections through the Windows App.
The issue affected certain Windows client builds connecting to:
- Azure Virtual Desktop
- Windows 365
- Remote environments accessed through the Windows App
Current status: Microsoft resolved this issue with the out-of-band update KB5077744. The resolution is also included in later cumulative Windows updates.
Outlook or Other Apps Freezing When Using Cloud Storage
Some applications could stop responding or display unexpected errors when opening or saving files stored through cloud services such as OneDrive or Dropbox.
Outlook could be affected when its PST data file was stored in OneDrive. Symptoms could include:
- Classic Outlook freezing or failing to reopen
- Outlook remaining active in the background
- Previously downloaded messages downloading again
- Sent items temporarily appearing to be missing
- Errors when opening or saving cloud-hosted files
Current status: Microsoft resolved this issue through KB5078127 and subsequent cumulative updates.
Missing Password Icon on the Lock Screen
Some enterprise or managed devices could display an invisible password icon within the lock-screen sign-in options. The password button remained selectable, even though its icon was not visible.
This issue originated with an earlier Windows update rather than KB5074109 itself. Microsoft resolved it in KB5074105.
What About Black Screens, GPU Problems or Shutdown Failures?
Individual users may report display, graphics, shutdown or performance problems after almost any major Windows update. However, Microsoft did not list general black-screen, graphics-driver or shutdown failures as official known issues specifically caused by KB5074109.
If these symptoms appear after an update, check for newer Windows updates and install the latest graphics, chipset and device drivers from the PC or hardware manufacturer before assuming KB5074109 is the cause.
How to Install Windows 11 KB5074109
KB5074109 was originally delivered automatically through Windows Update. Because it has now been replaced by newer cumulative updates, most users will not see KB5074109 offered as a separate update.
Install Through Windows Update
- Open Settings.
- Select Windows Update.
- Click Check for updates.
- Download and install the latest cumulative update offered for your PC.
- Save your work and restart the computer when prompted.
If your device is still on an older January 2026 build, Windows Update should normally offer a newer cumulative package containing the KB5074109 fixes.
Download KB5074109 From the Microsoft Update Catalog
IT administrators or users maintaining an offline system can still locate the standalone package in the Microsoft Update Catalog.
- Search for KB5074109.
- Identify whether the device runs Windows 11 24H2 or 25H2.
- Select the correct architecture, either x64 or ARM64.
- Review Microsoft’s package prerequisites and installation order.
- Download the required MSU files.
- Run the installer with administrator privileges.
- Restart the device after installation.
Important: Microsoft notes that the standalone installation may contain more than one MSU package. Follow the installation order shown on Microsoft’s support page rather than installing individual files at random.
How to Check Whether KB5074109 Is Installed
Check Windows Update History
- Open Settings.
- Go to Windows Update.
- Select Update history.
- Look under Quality Updates for KB5074109.
Check Your Windows Build Number
- Press Windows key + R.
- Type winver.
- Press Enter.
- Review the version and OS build displayed.
Immediately after the January 2026 update, Windows 11 24H2 displayed Build 26100.7623 and Windows 11 25H2 displayed Build 26200.7623. A higher build number generally means that a newer cumulative update has already been installed.
What to Do If KB5074109 Causes Problems
Because Microsoft has already released fixes for the main KB5074109 issues, the first troubleshooting step should normally be to install the newest available Windows update.
1. Install All Available Windows Updates
Go to Settings > Windows Update > Check for updates. Install all available cumulative updates, restart the computer and check whether the issue remains.
2. Update Your Device Drivers
Install current graphics, chipset, network and storage drivers from your computer manufacturer. Driver conflicts can sometimes appear immediately after a Windows update, even when the Windows package itself is not defective.
3. Repair Windows System Files
Open Command Prompt as an administrator and run:
DISM /Online /Cleanup-Image /RestoreHealthAfter DISM finishes, run:
sfc /scannowRestart the computer after both scans are complete.
4. Uninstall the Update Only as a Last Resort
- Open Settings.
- Select Windows Update.
- Open Update history.
- Select Uninstall updates.
- Find KB5074109 and select Uninstall, if the option is available.
Removing a security update can leave the device exposed to vulnerabilities. Use this option only when a serious problem prevents normal operation and a newer corrective update is unavailable.
Should You Install Windows 11 KB5074109?
You should keep the security fixes included in KB5074109, but you normally do not need to install this specific package manually today.
Windows 11 cumulative updates include fixes from previous releases. Installing the latest update offered through Windows Update gives you the KB5074109 security improvements together with newer protections and reliability fixes.
Organisations using managed deployment systems should test new cumulative updates against critical applications before broad deployment. This is especially important for environments that depend on Windows 365, Azure Virtual Desktop, remote-support software or automated credential workflows.
For a broader look at the operating system, see our guide to the latest Windows 11 features and improvements.
Upgrade to Windows 11 Pro
If your current PC supports Windows 11 but is still running an older Windows edition, upgrading can provide newer security protections, productivity features and business-management tools.
Get Windows 11 Pro from Brytesoft with instant digital delivery, activation support and a lifetime warranty.
FAQ About Windows 11 KB5074109 Update: Fixes, Issues and Install Guide
What is Windows 11 KB5074109?
KB5074109 is a cumulative security and quality update released by Microsoft on January 13, 2026, as part of the monthly Patch Tuesday cycle. It applies to supported versions of Windows 11, including 24H2 and 25H2. The update includes fixes for security vulnerabilities, performance improvements, and reliability enhancements. It also bundles all previously released updates into a single package.
Is KB5074109 a mandatory update?
Yes, KB5074109 is considered a mandatory update because it contains important security fixes. For most users, it will download and install automatically through Windows Update unless updates are paused. Organizations using update management tools may control their deployment. Skipping the update could leave systems exposed to known security risks.
What problems have been reported with KB5074109?
Some users have reported issues after installing KB5074109, including Outlook freezing when using POP email accounts. Others have experienced Remote Desktop connection problems, brief black screen display issues, or shutdown and hibernation failures. Not all systems are affected, and Microsoft has acknowledged several of these issues. In some cases, follow-up fixes have already been released.
Can I uninstall KB5074109 if it causes issues?
Yes, KB5074109 can be uninstalled if it causes serious problems on your system. You can remove it by going to Settings > Windows Update > Update history > Uninstall updates and selecting KB5074109. However, uninstalling the update will also remove important security patches. It’s recommended to reinstall the update once Microsoft provides a fix.
How do I know if KB5074109 is installed on my PC?
You can confirm installation by opening Settings > Windows Update > Update history and checking for KB5074109 in the list. Another option is to press Win + R, type winver, and verify that your Windows build number matches the KB5074109 release. Both methods help ensure your system is fully up to date.
