October 14, 2025—KB5066835 (OS Builds 26200.6899 and 26100.6899)
Applies To
Release Date:
14/10/2025
Version:
OS Builds 26200.6899 and 26100.6899
Windows Secure Boot certificate expirationImportant: Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. This might affect the ability of certain personal and business devices to boot securely if not updated in time. To avoid disruption, we recommend reviewing the guidance and taking action to update certificates in advance. For details and preparation steps, see Windows Secure Boot certificate expiration and CA updates.
To learn more about Windows update terminology, see types of Windows updates and monthly quality update types. For an overview, see the update history page for Windows 11, version 24H2 and version 25H2.
Stay informed! Follow @WindowsUpdate for the latest updates from the Windows Release Health Dashboard.
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Windows Updates do not include updates for Microsoft Store apps. If you're an enterprise user, see Microsoft Store apps - Configuration Manager. If you're a consumer user, see Get updates for apps and games in Microsoft Store. |
Highlights
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This update addresses security issues for your Windows operating system.
Improvements
This security update contains fixes and quality improvements from KB5065789 (released September 29, 2025). The following summary outlines key issues addressed by this update. Also, included are available new features. The bold text within the brackets indicates the item or area of the change.
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[Browser] Fixed: This update addresses an issue that caused the print preview screen to stop responding in Chromium-based browsers.
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[Gaming] Fixed: An issue occurred when users signed in to a Windows device using only a Gamepad at the lock screen. If no other input methods—such as touch or fingerprint—were used during sign-in, apps and games did not respond to input afterward.
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[PowerShell]
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Fixed: This update addresses an issue that affects PowerShell Remoting and Windows Remote Management (WinRM), where commands might time out after 10 minutes.
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Fixed: This update addresses an issue that prevented an audit event from being logged.
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[Windows Hello] Fixed: This update addresses an issue that affects the setup process for Windows Hello face recognition when using USB infrared camera modules. Users were unable to complete setup due to a persistent error message, such as “Make sure your face is centered in the frame.”
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[Compatibility] This update removes the ltmdm64.sys driver. Fax modem hardware dependent on this specific driver will no longer work in Windows.
If you've already installed previous updates, your device will download and install only the new updates included in this package.
For more information about security vulnerabilities, see the Security Update Guide website and the October 2025 Security Updates.
AI Components
This release updates the following AI components:
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AI Component |
Version |
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Image Search |
1.2509.1022.0 |
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Content Extraction |
1.2509.1022.0 |
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Semantic Analysis |
1.2509.1022.0 |
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Settings Model |
1.2509.1022.0 |
Windows 11 servicing stack update (KB5067360)- 26100.6893
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates. To learn more about SSUs, see Simplifying on-premises deployment of servicing stack updates.
Known issues in this update
Symptoms
Some Digital TV and Blu-ray/DVD apps might not play protected content as expected after installing the August 29, 2025, Windows non-security preview update (KB5064081), or later updates.
Apps that use Enhanced Video Renderer with HDCP enforcement or Digital Rights Management (DRM) for digital audio might show copyright protection errors, frequent playback interruptions, unexpected stops, or black screens.
Streaming services are not affected.
Workaround
This issue is partially resolved. Problems affecting certain applications that use Enhanced Video Renderer with HDCP enforcement have been addressed in the September 2025 Windows preview update (KB5065789) and later updates.
We recommend installing the latest update for your device. It includes important improvements and fixes, including a resolution for this issue.
However, some apps that use DRM for digital audio might still experience problems.
We’re investigating a long-term solution for affected apps and will share more information when it's available.
How to get this update
Before you install this update
Microsoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.
Install this update
To install this update, use one of the following Windows and Microsoft release channels.
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Available |
Next Step |
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This update downloads and installs automatically from Windows Update and Microsoft Update. |
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Available |
Next Step |
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This update downloads and installs automatically from Windows Update for Business in accordance with configured policies. |
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Available |
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Yes 1 |
Before you install this update To get the standalone package(s) for this update, go to the Microsoft Update Catalog website. This KB contains one or more MSU files that require installation in a specific order. Install this update Method 1: Install all MSU files together Download all MSU files for KB5066835 from Microsoft Update Catalog and place them in the same folder (for example, C:/Packages). Use Deployment Image Servicing and Management (DISM.exe) to install the target update. DISM will use the folder specified in PackagePath to discover and install one or more prerequisite MSU files as needed. Updating Windows PC To apply this update to a running Windows PC, run the following command from an elevated Command Prompt:
Or, run the following command from an elevated Windows PowerShell prompt:
Or use Windows Update Standalone Installer to install the target update. Updating Windows Installation media To apply this update to Windows Installation media, see Update Windows installation media with Dynamic Update. Note: When downloading other Dynamic Update packages, ensure they match the same month as this KB. If the SafeOS Dynamic Update or Setup Dynamic Update is not available for the same month as this KB, use the most recently published version of each. To add this update to a mounted image, run the following command from an elevated Command Prompt:
Or, run the following command from an elevated Windows PowerShell prompt:
Method 2: Install each MSU file individually, in order Download and install each MSU file individually either using DISM or Windows Update Standalone Installer in the following order:
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1 This latest cumulative update includes updates for AI components. Even though the AI component updates are included in the update, the AI components are only applicable to Windows Copilot+ PCs and will not install on Windows PC or Windows Server.
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Available |
Next Step |
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This update automatically syncs with Windows Server Update Services (WSUS) if you configure Products and Classifications as follows: Product: Windows 11 Classification: Security Updates |
If you want to remove the LCU
To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.
Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.
File information
For a list of the files provided in this update, download the file information for cumulative update 5066835.
For a list of the files provided in the servicing stack update, download the file information for the SSU (KB5067360) - version 26100.6893.
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