What does KB5129195 fix and do I need to install it manually?

KB5129195 is the September 14, 2026 out-of-band cumulative update for Windows 11 24H2 (build 26100.9457) and 25H2 (build 26200.9457). It repairs Remote Desktop Services instability, Hyper-V Plan 9 shared folders for HCS-managed Linux VMs, and USB Audio Class 1.0 multichannel failures, and adds protection for CVE-2026-62721. Home users receive it automatically through Windows Update; WSUS syncs it; manual installers can download the MSU from the Microsoft Update Catalog (Microsoft Support, Sep 14

Will Copilot Chat in Outlook really work without a paid Copilot license?

Roadmap item ID 554934, listed in the September 10, 2026 roundup, extends Copilot Chat in Outlook to reason over a user’s inbox, calendar, and enterprise data without requiring a Copilot license. Roadmap entries do not carry ship dates, so treat it as rolling availability. The practical takeaway is that AI access is broadening, which is a good moment to review sensitivity labels and DLP policies (M365 Roadmap Roundup, Sep 10, 2026).

When can I sync 1 million files with OneDrive?

Roadmap ID 560549 raises the OneDrive sync limit from 300,000 to 1 million items on Windows, starting as a preview for Insiders. Devices that do not meet the qualification criteria stay at 300,000, and Microsoft has not yet published those criteria in the sources we verified. Watch the Microsoft 365 roadmap and Insider release notes for the rollout (M365 Roadmap Roundup, Sep 10, 2026).

What is DLP OCR on Windows endpoints?

It is a Microsoft Purview data-loss-prevention capability, roadmap ID 160008, that applies optical character recognition to images on Windows endpoints so policies can detect sensitive text inside JPG, PNG, TIFF, BMP, and image-only PDF files. A matching capability is planned for macOS under ID 410247. It targets the common exfiltration path of screenshotting sensitive data before it leaves the device (M365 Roadmap Roundup, Sep 10, 2026).

My USB audio device still fails after updating. What now?

KB5129195 fixes multichannel failures such as 8-channel or 3D audio modes on USB Audio Class 1.0 devices, but the known-issues section of the KB entry notes that some symptoms, including Code 10 startup errors and unresponsive volume controls, remain under investigation. Keep the device firmware current, reinstall the USB controller driver as a first step, and watch the KB page for the follow-up fix (Microsoft Support, Sep 14, 2026).

Windows & Microsoft AI News: KB Fix & Copilot (Sep 15, 2026)