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Windows 10 1607 Windows 10 1607 Out-of-band update
Out-of-band

KB5129239

KB5129239: Cumulative update for Windows 10, version 1607, September 2026. Remote Desktop instability and multichannel USB audio addressed

In short

Addresses Remote Desktop instability and fixes failures in 8-channel or 3D audio on some USB Audio Class 1.0 devices. Other USB audio symptoms remain unresolved.

Does it affect you? Applies to: Devices running Windows 10 Enterprise LTSB 2016 or Windows 10 IoT Enterprise 2016 LTSB, version 1607, build 14393.9514.

Build
14393.9514
Restart
Required

Microsoft publishes separate notes for this KB for Windows Server.

What changes

Fixes 2 changes

Remote Desktop Services (known issue)

Verified in package
  • Addresses Remote Desktop instability that could cause connection or sign-in failures, unresponsive servers, and related tools to stop responding.1
    The issue could affect Remote Desktop configuration and tools including Microsoft Management Console (MMC), RDS Licensing Diagnoser, File Explorer, and the Windows Update page.

8-channel or 3D audio modes

Verified in package
  • Some USB Audio Class 1.0 devices that worked in standard stereo no longer fail when using 8-channel or 3D audio modes.2
    The update resolves the multichannel audio symptoms; other USB Audio Class 1.0 symptoms remain unresolved.

Known issues

  1. Open Affects: Everyone

    USB Audio Class 1.0 devices with error Code 10 or no output

    Some USB Audio Class 1.0 devices might still fail to start or produce sound after the update, including Code 10 errors, no audio output, unresponsive volume controls, or unavailable sound settings. The update resolves the symptoms with 8-channel or 3D audio modes, but not these other symptoms.3

    How to apply the workaround Workaround

    IT administrators who need an immediate workaround for the remaining symptoms can contact Microsoft Support for Business.3

  2. Open Affects: Everyone

    File History might stop working after installing September 2026 Windows update

    Some people using File History might be unable to create or update backups after the September 2026 Windows security update. The drive might be reported as disconnected even when it is connected, and backup timestamps or previous file versions might be unavailable.4

    Workaround status No workaround yet

    Microsoft has not published a manual workaround for this issue yet. Monitor release health until a resolving update is available.

Technical details

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

Data sheet

Released
2026-09-14
Classification
Updates
Type
Cumulative update
Restart
Required
Replaces
KB5123099, KB5120418, KB5099535, KB5094122
+23 earlier KB5087537, KB5091572, KB5082198, KB5078938, KB5075999, KB5073722, KB5074974, KB5071543, KB5068864, KB5066836, KB5065427, KB5063871, KB5062560, KB5061010, KB5058383, KB5058921, KB5055521, KB5053594, KB5052006, KB5049993, KB5048671, KB5046612, KB5037423
Replaced by
KB5126868
VersionBuildChannel
1607 14393.9514 General availability

Security

No vulnerabilities are listed for this update.

Updated components

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

Top changed componentsFiles
Remote Desktop9
Audio2
Kernel2
Printing2

Verified in package: changed files confirm Remote Desktop Services (known issue), 8-channel or 3D audio modes.

Sources

Updated
Cited passages from Microsoft's official notes (4)
  1. 1. In affected environments, RDS might become unstable, causing RDP connection and sign-in failures or servers to become unresponsive during Remote Desktop configuration. support.microsoft.com
  2. 2. Fixed: Some USB Audio Class 1.0 devices functioning as expected in standard stereo configurations failed when using multichannel audio features, including 8-channel or 3D audio modes. support.microsoft.com
  3. 3. This OOB update resolves the symptoms experienced on devices using 8-channel or 3D audio modes (last bullet point in the list of symptoms documented in this entry). We are working to address the other symptoms learn.microsoft.com
  4. 4. After installing the September 2026 Windows security update KB5124008, some customers using File History, might be unable to create or update backups. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 4 quoted passages · compared with Microsoft's page on Sep 25, 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