KB5129236


Microsoft has released an out-of-band cumulative update KB5129236 for Windows 10, version 22H2, after Patch Tuesday. It fixes Remote Desktop Services failures, inaccessibility of shared folders in Linux systems on Hyper-V, and failure of multichannel audio on USB Audio Class 1.0 devices. The out-of-band update KB5129236 (Build 19045.7727) was released on September 14, 2026 outside the regular schedule and is also being distributed for Windows 10, version 21H2 (build 19044.7727). The update is cumulative and includes all security fixes and improvements from the September 8, 2026 security update (KB5122878).

This update does not fix other audio issues: some USB Audio Class 1.0 devices still do not play sound, and Device Manager displays error Code 10.

Along with the cumulative update, the servicing stack update KB5122877 (version 19041.7714) is installed, which improves the reliability of the Windows update installation process.

Note. The out-of-band update KB5129236 is not offered through Windows Update – it can only be downloaded manually from the Microsoft Update Catalog. A computer restart is required to complete the installation. After the update, the Windows 10 build number (version 22H2) will change to 19045.7727.

Feature / Change Performance Increase/Decrease Optimization PC Speed Gaming Optimization
Remote Desktop Services (RDS) – fix for instability after KB5122878: RDP connections and sign-ins failed, servers stopped responding during remote desktop configuration; MMC, RDS Licensing Diagnoser, File Explorer, and Windows Update page could hang 🟢 High increase (restores previously lost performance; eliminates hangs in MMC, RDS Licensing Diagnoser, File Explorer, and Windows Update page) 🟢 High (RDS stack stability restored; sign-in and connection flows work again) 🟢 High (servers stop freezing during remote desktop configuration; no more unresponsive sessions) ⚪ No direct impact (server/enterprise remote access scenario, not gaming)
Hyper-V – fix for HCS-managed virtual machines: folders shared by the host with Linux guests over the Plan 9 protocol did not appear or were inaccessible in the guest environment 🟢 Medium increase (shared folders accessible again; removes I/O stall caused by failed Plan 9 mounts) 🟢 Medium (host–guest file sharing over Plan 9 works as expected) 🟡 Low–Medium (eliminates delays when accessing shared folders from Linux guests) ⚪ No direct impact (virtualization/server scenario, not gaming)
8-channel and spatial audio – fix for USB Audio Class 1.0 devices: devices that worked in normal stereo mode failed when using multichannel audio (8-channel or spatial) 🟢 Medium increase (multichannel and spatial audio output restored on affected USB Audio Class 1.0 devices) 🟢 Medium (audio pipeline no longer fails when switching from stereo to 8-channel/spatial) ⚪ No impact (audio subsystem only, no effect on general PC speed) 🟡 Medium (spatial/multichannel audio works again for games that use it)
Known issue not fixed – some USB Audio Class 1.0 devices still do not play sound; Device Manager displays error Code 10 🔴 Decrease (no sound output on affected devices; functionality remains broken) 🔴 None (issue unresolved in this update) ⚪ No impact (no effect on general PC speed) 🔴 Decrease (no audio in games on affected USB Audio Class 1.0 devices)

Find and Change Settings

Setting Where to find How to change
Remote Desktop Services stability Settings > Windows Update Install the latest cumulative update through Settings > Windows Update to resolve RDP connection failures, sign-in errors and server unresponsiveness that occurred after KB5122878. No additional configuration is required.
Hyper-V Plan 9 shared folders Settings > Windows Update Install the latest cumulative update through Settings > Windows Update to restore access to host-shared folders using the Plan 9 protocol in HCS-managed virtual machines. No additional configuration is required.
8-channel and spatial audio for USB Audio Class 1.0 Settings > Windows Update Install the latest cumulative update through Settings > Windows Update to fix failures of USB Audio Class 1.0 devices in 8-channel or spatial audio mode. No additional configuration is required.

Official announcement on the Microsoft website.

The last 10 Windows updates:

Update Build Version Windows Channel Date
KB5124006 28000.3086 26H1 Windows 11 Preview 2026-09-22
KB5124010 26200.9550 26H2 Windows 11 Preview 2026-09-22
KB5124138 28120.3032 26H1 Windows 11 Experimental 2026-09-18
KB5124140 26220.9492 25H2 Windows 11 Beta 2026-09-18
KB5124137 26340.9502 26H2 Windows 11 Experimental 2026-09-18
KB5129242 22631.7584 23H2 Windows 11 Stable 2026-09-14
KB5129236 19045.7727 22H2 Windows 10 Stable 2026-09-14
KB5129195 26300.9457 26H2 Windows 11 Stable 2026-09-14
KB5129194 28000.2956 26H1 Windows 11 Stable 2026-09-14
KB5124115 26220.9472 25H2 Windows 11 Beta 2026-09-11