Microsoft’s September 14 emergency Windows update repairs Remote Desktop failures and a specific USB sound problem—but it does not clear every audio fault introduced by last week’s security update. For Windows 11 24H2 and 25H2, KB5129195 fixes multichannel playback while USB Audio Class 1.0 devices showing Code 10 or producing no sound remain a known issue.
That distinction matters before you reinstall a driver or assume the update failed. A headset that works in stereo but stops in an eight-channel mode and a device that cannot start have different outcomes in this release.
One audio problem gets a fix; another stays open
The repaired case involves some USB Audio Class 1.0 devices that function in ordinary stereo but fail when using eight-channel or 3D audio. Microsoft lists that behavior among the fixes in the new cumulative update.
The unresolved case is broader loss of operation after the September 8 security update: Device Manager may show This device cannot start (Code 10), sound may disappear, the volume may stay at zero, or sound settings may stop responding. Microsoft says it is working on a resolution.
- Stereo works, but eight-channel or 3D audio fails: the update lists a fix for this USB Audio Class 1.0 behavior.
- Code 10, no output, or stuck volume controls: these remain known issues after the update.
Record the device model, the exact error and when it started. A high-CPU audio process is a different diagnostic problem; our Audiodg.exe guide covers that situation. Neither symptom alone identifies malware.
Remote Desktop and shared Linux folders also receive repairs
The same release addresses Remote Desktop Services instability following September’s security updates. The reported effects include connection or sign-in failures and unresponsive management tools. It also fixes a separate Hyper-V problem in which applications using HCS-managed Linux virtual machines could not access Windows folders shared through Plan9.
These are specific regression fixes, not reasons to change an account’s sign-in policy or open Remote Desktop to the internet. If the actual error says account restrictions prevent sign-in, use the account-restrictions troubleshooting guide to distinguish that condition.
Check your Windows version before choosing a package
KB5129195 applies to Windows 11 24H2 and 25H2, bringing them to builds 26100.9457 and 26200.9457, respectively. Other Windows releases use different packages. Check your version with winver, then use Windows Update or your organization’s normal update process.
Microsoft distributes this cumulative release automatically through Windows Update; it also includes an additional security protection for the Windows User-Mode Power Service. After installation and any requested restart, check the build and repeat the specific task that was failing. If Code 10 persists on an affected USB Audio Class 1.0 device, keep that symptom distinct from the multichannel fix and follow Microsoft’s known-issue entry for the next resolution.
References
- Microsoft. “September 14, 2026—KB5129195 (OS Builds 26200.9457 and 26100.9457) Out-of-band.” Updated September 14, 2026; accessed September 15, 2026. Microsoft Support.
