Windows Update · reviewed KB record
KB5129195
September 14, 2026 Windows 11 out-of-band update
A cumulative out-of-band follow-up to the September security update. It is especially relevant when troubleshooting documented RDS instability, Plan9 host-folder sharing, or multichannel USB-audio failures introduced around the September update cycle.
Released: 2026-09-14Reviewed: 2026-09-17Type: Out-of-band cumulative update
Release status
Released; resolves several September known issues
Windows releases
Windows 11 25H2 · Windows 11 24H2
OS builds
25H2 — 26200.9457 · 24H2 — 26100.9457
Documented known-issue context
- USB Audio Class 1.0 devices can still have Code 10, no-output, unresponsive-volume or unavailable-Sound-settings symptoms; Microsoft documents that those remaining symptoms are not fully resolved by this OOB update.
Later resolution or status change
- Resolves the documented Remote Desktop Services instability after the September 2026 security update.
- Resolves the documented Plan9 host-folder-share problem for HCS-managed Linux VMs.
- Resolves the documented 8-channel/3D multichannel symptom for affected USB Audio Class 1.0 devices.
Do not infer causation from timing alone
An issue beginning after an update can still be caused by a driver, peripheral, application or hardware change. Use Microsoft’s documented affected platforms and issue state, then confirm the symptom matches.
Evidence
Microsoft sources reviewed
Update records preserve the source and review date because release-health status can change after publication.