KB5127646: Windows 11 version 26H1 Security Update (October 2026)

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

Symptoms

After installing the September 2026 non-security preview update KB5124006 , 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 is addressed by Windows updates released on and after October 27, 2026 ( KB5127653 ). We recommend you install the latest update for your device as it contains important improvements and issue resolutions, including this one.

If you install an update released October 27, 2026 ( KB5127653 ) or later, you do not need to use a workaround for this issue. If you are using an update released before October 27, 2026, and have this issue, you have the option to apply the following workaround.

Workaround

IT administrators can mitigate this issue on devices affected by the Remote Desktop connection failure by using their existing policy management method to temporarily turn off Administrator protection. Reset the User Account Control Type Of Admin Approval Mode policy in Microsoft Intune or Group Policy. For more information, see Administrator protection on Windows 11 .

2. USB audio devices might fail to start or produce no sound

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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).”

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No audio output.

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Volume controls are unresponsive or remain at zero.

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Sound settings are unresponsive or unavailable.

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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

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. Microsoft is working to address the other symptoms and will provide more information when it is available.

IT administrators who need an immediate workaround for the symptoms not addressed yet by the OOB update should contact Microsoft Support for Business for assistance.