Windows 11 · 26H2 · Release · Out-of-band update

Windows 11, version 26H2 (26300.9725)

Windows 11 26H2: Current annual release; availability depends on device eligibility and rollout

Microsoft release information · Verified Oct 26, 2026

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AI summary

Windows 11, version 26H2 (OS Build 26300.9725) is identified as a Release Preview build and corresponds to the October 26, 2026 out-of-band cumulative update KB5134133. It includes an updated trusted-root certificate payload for devices that can’t receive automatic certificate trust list updates. (support.microsoft.com)

Generated from the package's release notes and forum coverage. Verify against Microsoft's release-health page before acting on it.

Microsoft's known issues — KB5134133

  • Issue Known issue 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. 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 Workaround: Important: This section contains information about modifying the registry. Before you modify the registry, back it up and make sure that you know how to restore it if a problem occurs. For more information, see How to back up and restore the registry in Windows . Option #1: Modify the registry You can modify the registry to restore the ability to turn on Smart App Control by following these steps: Open a Command Prompt window by typing cmd in the Search box. Open a Command Prompt window by typing cmd in the Search box. Select Run as administrator . Select Run as administrator . At the command prompt, enter the following commands. Then restart the device. reg add "HKLM\SYSTEM\CurrentControlSe

Microsoft's release notes for KB5134133 ›

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