In this article, we will talk about a New Windows 11 25H2 Emergency Update, that Microsoft released to apply multiple fixes for some Issues caused by the Windows 11 25H2 September 2026 Security Update.
This out-of-band (OOB) update for Windows 11, version 25H2 and Windows 11, version 24H2 (KB5129195) is cumulative. It includes updates from previous releases, along with additional security and non-security improvements. Visit the Windows release health dashboard for the latest status on this release.
New Improvements in this Update
- [Security] This update includes protections documented in CVE-2026-62721, which refers to a Windows User-Mode Power Service (UMPS) Elevation of Privilege vulnerability.
- [Remote Desktop Services (known issue)] Fixed: This update addresses an issue affecting Remote Desktop Services (RDS) after installing the September 2026 Windows security update (KB5122880). In affected environments, RDS might become unstable, causing RDP connection and sign-in failures or servers to become unresponsive during Remote Desktop configuration. Related tools, including Microsoft Management Console (MMC), RDS Licensing Diagnoser, File Explorer, and the Windows Update page, might also stop responding.
- [Hyper-V (known issue)] Fixed: Some applications that use HCS-managed virtual machines experienced issues when sharing host folder with Linux VMs using Plan9. Folders shared from the Windows host using Plan9 did not appear or could not be accessed in the guest environment.
- [8-channel or 3D audio modes] 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.
For additional information related to all of these Issues, you can check this article from Microsoft.
Known Issues in this Update
USB Audio Class 1.0 devices with error Code 10 or no output
After installing the September 8, 2026, Windows security update, 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.
This issue is limited to USB Audio Class 1.0 devices.
Microsoft is working on a resolution and will update the official documentation when more information is available.
How to Install this Update
To install this Update, simply Check for Updates in the Settings App through the Windows Update Section.
For more info about this Update, you can check this article from the Microsoft Blog.
For a more in-depth presentation of the New Update, you can watch the video below from the YouTube channel.
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