October 13, 2026—KB5127648 (OS Builds 26300.9711, 26200.9711 and 26100.9711)

Applies To
Windows 11 version 26H2, all editions Windows 11 version 25H2, all editions Windows 11 version 24H2, all editions
Want a quick overview?: Watch the Windows 11 release note video for this update.

Announcements and messages

This section provides key notifications related to this release, including announcements, change logs, and end-of-support notices.

Important

Windows 11, version 24H2 Home and Pro has reached end of updates. The October 2026 monthly security update is the last update available for these editions. Devices running these editions will no longer receive monthly security and non-security preview updates containing protections from the latest security threats. To stay protected and up to date, we recommend you upgrade to the latest version of Windows 11.

Windows Secure Boot certificate expiration

Secure Boot certificate updates remain in progress as Microsoft transitions devices from certificates that began expiring in 2026 to newer certificates. Devices that have not yet received the newer certificates can continue to start and receive standard Windows updates. Microsoft will continue delivering the newer Secure Boot certificates to eligible devices through Windows Update.

Improvements

This update includes improvements from the following previously released updates:

The following summary outlines key quality improvements addressed by this update. The bold text within the brackets indicates the item or area of the change.

  • [Security updates] This update provides security improvements. For more information about the security vulnerabilities resolved by this update, see the Security Update Guide.

  • [Secure Boot] This update continues the deployment of updated Secure Boot certificates using the latest high-confidence targeting data to identify eligible devices that are ready to automatically receive the new certificates. Deployment through Windows Update remains ongoing across supported devices.

  • [Windows Explorer (Known issue)] Fixed This update fixes an issue that affects Windows Explorer in multi-user environments, such as Azure Virtual Desktop and FSLogix. After sign-in, Explorer.exe might fail to start or repeatedly crash, causing a black screen.

  • [Audio (known issue)] Fixed This update fixes an issue that affects AC-3 audio playback in some applications.

  • [Storage Spaces] This update fixes an issue that affects tiered Storage Spaces Direct virtual disks. Some virtual disks might fail to come online after installing certain security updates, making dependent clustered workloads unavailable.

  • [Date and Time] This update introduces the new (UTC-05:00) Manitoba time zone to support Manitoba’s November 1, 2026, time zone change.

  • [ReFS security] This update adds auditing and optional policy controls for ReFS volumes on externally attached storage devices. Auditing is enabled by default, while enforcement controls remain disabled by default to give administrators time to evaluate and prepare for future security hardening changes. To learn more, see KB5130741.

  • [Printing] This update resolves an issue where printing could fail in some applications and on devices using RAW or Generic Text Only printer drivers after installing the August 2026 security update.

  • [Gaming] This update fixes an issue that could cause mouse input to stutter in some games.

  • [Windows Hello] This update fixes an issue where fingerprint sign-in might not work after a cold boot on some devices.

  • [Authentication] This update strengthens NTLMv1 security by changing the internal default behavior when the BlockNtlmv1SSO registry value is not set. Windows now uses Enforce mode (1) instead of Audit mode (0), blocking the generation of NTLMv1-derived credentials for Single Sign-On (SSO). This change applies only to devices where Credential Guard is disabled and the BlockNtlmv1SSO registry value is not set, and might affect Wi-Fi, Ethernet, and VPN connections that use MS-CHAPv2-based authentication. For more information, see KB5066470.

If you've already installed previous updates, your device will download and install only the new updates included in this package.

Components updates

AI components

This release updates the following AI components to version 1.2608.951.0: Image Search, Content Extraction, Semantic Analysis, and Settings Model. To learn more, see Release information for AI components.​

Servicing stack update

Includes KB5127647 (Build 26100.9703), which improves the reliability of the Windows update installation process. To learn more about SSUs, see Servicing stack updates.

Known issues in this update

You might be unable to turn on Smart App Control

Symptoms

After installing this update, some devices might be unable to turn on Smart App Control in the Windows Security app if it has been turned off. On affected devices, the option to turn on Smart App Control might be grayed out.

Devices where Smart App Control is already turned on are not affected and remain protected.

Resolution

This issue was resolved for Windows 11, versions 26H2 and 25H2, by Windows updates released on and after October 28, 2026 (KB5127936). This issue was resolved for Windows 11, version 24H2, by Windows updates released on or after November 10, 2026 (KB5132061).

We recommend you install the latest update for your device as it contains important improvements and issue resolutions, including this one.

Remote Desktop connections might fail for non-admin users with error 0xC000000D

Symptoms

After installing the September 2026 non-security preview update KB5124010, or later updates, non-admin users might be unable to establish Remote Desktop connections to remote devices that have Administrator protection enabled. Attempts to connect might fail with error 0xC000000D and display the message, “The token that was passed to the function is invalid.” This issue primarily affects enterprise-managed remote devices used as Remote Desktop hosts with Administrator protection enabled, regardless of how the feature was enabled.

Note: If your organization uses Windows security baselines, published through the Microsoft Security Compliance Toolkit, Administrator protection is enabled by default in Windows 11, version 24H2, 25H2, and 26H2 security baselines, unless your organization has configured the policy differently.

Resolution

This issue was resolved for Windows 11, versions 26H2 and 25H2, by Windows updates released on and after October 28, 2026 (KB5127936). This issue was resolved for Windows 11, version 24H2, by Windows updates released on or after November 10, 2026 (KB5132061).

We recommend you install the latest update for your device as it contains important improvements and issue resolutions, including this one.

USB audio devices might fail to start or produce no sound

Symptoms

After installing the September 8, 2026, Windows security update (KB5124012), some USB Audio Class 1.0 devices might fail to start or produce audio. Affected devices might experience one or more of the following symptoms:

  • The device displays an error in Device Manager: "This device cannot start (Code 10).”

  • No audio output.

  • Volume controls are unresponsive or remain at zero.

  • Sound settings are unresponsive or unavailable.

Some devices might function in standard stereo configurations but fail when using multichannel audio features, including 8-channel or 3D audio modes. Some customers have reported that they're able to restore audio in these cases by switching to 2-channel mode.

This issue is limited to USB Audio Class 1.0 devices.

Resolution

The symptoms experienced on devices using 8-channel or 3D audio modes are addressed in the out-of-band (OOB) update released on September 14, 2026, (KB5129195). The remaining symptoms are addressed in (KB5132061).

How to get this update

Before you install this update

  • For Windows Update: For Windows 11, version 24H2 and Windows 11, version 25H2, you must have the Windows update released on or after June 10, 2025 (such as KB5060842) installed before installing this update.

  • For Windows Server Update Services (WSUS) deployment or when installing the standalone package from Microsoft Update Catalog: For Windows 11, version 24H2 and Windows 11, version 25H2, you must have the Windows update released on or after June 10, 2025 (such as KB5060842) installed before installing this update.

  • For Servicing Stack Update (SSU): You must have the latest SSU installed to install this update.

Deployment

If you deploy dynamic updates such as this update to an existing Windows image, ensure the boot.stl file is included as part of the installation media. Failure to include the file might prevent devices from successfully starting from the installation media and can result in error code 0xc0430001.

Note

The boot.stl file is used during Secure Boot validation and must match the Windows version and architecture of the image you are updating.

To ensure the boot.stl file is included as part of the installation media, do one of the following:

  • Use the Update WinPE script to update an existing Windows image. (Recommended)
  • Manually copy the boot.stl file from the device Windows\Boot\EFI folder to the corresponding folder on your installation media before deploying the update.

For information about how to apply Dynamic Update packages to existing Windows images, see Update Windows installation media with Dynamic Update.

Install this update

To install this update, use one of the following Windows and Microsoft release channels.

Available Next Step
Available This update downloads and installs automatically from Windows Update and Microsoft Update.

File information

For a list of the files provided in this update, download the file information for cumulative update KB5127648.

For a list of the files provided in the servicing stack update, download the file information for the SSU KB5127647 - (Build 26100.9703).

Windows monthly updates explained

Description of the standard terminology used for Microsoft software updates

Microsoft Store for Business and Education with Configuration Manager

Get updates for apps and games in Microsoft Store

Change log
Change date Change description
November 10, 2026 Known issues resolved for Smart App Control, Remote Desktop connections, and USB Audio devices.
October 20, 2026 Removed information about a fix for an Always On VPN connection issue that was previously included in this article. This change will be included in a future release.
October 14, 2026 Known issue added: Remote Desktop connections might fail for non-admin users with error 0xC000000D.
October 15, 2026 Added a release note: "[Authentication] This update strengthens NTLMv1 security by changing the internal default behavior when the BlockNtlmv1SSO registry value is not set. Windows now uses Enforce mode (1) instead of Audit mode (0), blocking the generation of NTLMv1-derived credentials for Single Sign-On (SSO). This change applies only to devices where Credential Guard is disabled and the BlockNtlmv1SSO registry value is not set, and might affect Wi-Fi, Ethernet, and VPN connections that use MS-CHAPv2-based authentication. For more information, see KB5066470."