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Windows 11 26H1 Windows 11 26H1 Out-of-band update
Out-of-band Known issues

KB5134134

KB5134134: Cumulative update for Windows 11, version 26H1, October 2026. Offline devices receive updated trusted root certificates

In short

Devices that miss automatic certificate trust updates get an updated trusted-root payload. The package also updates AI components and improves update installation reliability.

Does it affect you? Applies to: Windows 11, version 26H1 devices, including Arm64 devices, that do not receive current certificate trust list updates. This includes disconnected devices, devices that cannot access Microsoft’s certificate-update service, and devices where automatic certificate trust list updates are disabled.

Build
28000.3237
Restart
Required

What changes

Improvements 3 changes

Certificates

For: Devices that do not receive current certificate trust list updates

  • Devices that cannot get certificate trust updates receive an updated trusted-root list in the Windows update.1
    Adds an updated trusted root certificate payload for devices that cannot access Microsoft’s certificate-update service or have automatic CTL updates disabled.

AI components

  • Four built-in AI components get a version update. These components apply only to Copilot+ PCs.2
    Updates Image Search, Content Extraction, Semantic Analysis, and Settings Model to version 1.2608.951.0.

Servicing stack

  • The Windows update installation process gets a reliability improvement.3
    Includes servicing stack update KB5127645, build 28000.3225.

Known issues

  1. Resolved Affects: Organizations and IT administrators Resolved by KB5127653

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

    Non-admin users might get error 0xC000000D when connecting to remote devices with Administrator protection enabled. It primarily affects enterprise-managed devices used as Remote Desktop hosts. KB5127653 or later resolves the issue.4

    How to apply the workaround Group Policy / Intune

    For affected devices using an update released before October 27, 2026, temporarily turn off Administrator protection by resetting the policy in Intune or Group Policy.4

  2. Resolved Affects: Everyone Resolved by KB5132059

    USB audio devices might fail to start or produce no sound

    Some USB Audio Class 1.0 devices might fail to start or produce no sound. KB5129194 partly resolves symptoms in 8-channel and 3D audio modes; other symptoms might remain.5

    How to apply the workaround Workaround

    Some customers report that switching to 2-channel mode restores audio. For symptoms not resolved by KB5129194, IT administrators can contact Microsoft Support for Business.5

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2026-10-26
Classification
Updates
Type
Cumulative update
Restart
Required
Replaces
KB5127646, KB5124006, KB5129194, KB5124012
+14 earlier KB5120996, KB5121000, KB5101681, KB5101649, KB5095091, KB5095051, KB5089570, KB5089548, KB5083806, KB5083768, KB5079489, KB5079466, KB5077239, KB5077179
Replaced by
KB5132059
VersionBuildChannel
26H1 28000.3237 General availability

Security

No vulnerabilities are listed for this update.

Updated components

206 files changed since the previous update for the same versions.

Top changed componentsFiles
Security and sign-in4

Sources

Updated
Cited passages from Microsoft's official notes (5)
  1. 1. This update includes an updated trusted root certificate payload in the Windows cumulative update for devices that cannot access Microsoft’s certificate-update service and devices where automatic certificate trust list (CTL) updates are disabled. support.microsoft.com
  2. 2. This release updates the following AI components to version 1.2608.951.0: Image Search, Content Extraction, Semantic Analysis, and Settings Model. support.microsoft.com
  3. 3. This Windows update includes KB5127645 (Build 28000.3225), which improves the reliability of the Windows update installation process. support.microsoft.com
  4. 4. This issue is addressed by Windows updates released on and after October 27, 2026 (KB5127653). support.microsoft.com
  5. 5. This issue is partially resolved in the out-of-band (OOB) update released on September 14, 2026, (KB5129194). This OOB update resolves the symptoms experienced on devices using 8-channel or 3D audio modes. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 5 quoted passages · compared with Microsoft's page on Nov 14, 2026
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: passed

A second AI read the text against the sources: correctness 5/5, clarity 4/5, completeness 5/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake