KB5127648

Microsoft has released cumulative update KB5127648 for Windows 11, version 26H2 (2026 Update) as part of the October 2026 Patch Tuesday. The package (Build 26300.9711) is intended for devices based on x64 (amd64) and ARM64 processors. On September 29, 2026, Windows 11, version 26H2 became generally available: the update is rolling out in phases, and the range of eligible devices will expand over the coming months. Versions 24H2, 25H2, and 26H2 share a common servicing branch, so they receive the same monthly updates.

This is a quality update, and it does not introduce new system features. The key changes and known issues are listed below.

• Security. The update contains various security improvements to internal OS functionality for October 2026. On Patch Tuesday, Microsoft fixed 1411 security issues, including three zero-day vulnerabilities.
• Changes from KB5124010. Includes all fixes and changes from the preview update KB5124010 (Build 26300.9550) for Windows 11, version 26H2. It brought support for Emoji 17.0, the Tips widget, one-finger scrolling on the touchpad, the ability to remap the Copilot key to the right Ctrl key or the context menu key, a Preview anyway button for HTML files from the internet in the File Explorer preview pane, a setting for OneDrive photo backup in Settings, as well as improvements to Bluetooth and Bluetooth audio and fixes for desktop wallpapers. In addition, domain trust relationship loss and File History failures have been fixed, and PC-to-PC data transfer has been removed in favor of Windows Backup. Most of the new features are rolling out in phases.
• Secure Boot. The rollout of updated Secure Boot certificates continues. Up-to-date high-confidence data is used to identify devices that are ready to receive the new certificates automatically. Distribution through the Windows Update service continues on supported devices.
• Windows Explorer. Fixed an issue with Explorer in multi-user environments, including Azure Virtual Desktop and FSLogix. After sign-in, the Explorer.exe process might fail to start or crash repeatedly, causing a black screen.
• Audio. Fixed an issue with AC-3 audio playback in some apps.
• Always On VPN. Fixed an issue with Always On VPN connections after installing KB5124008. If automatic protocol selection or protocol fallback was configured, the VPN connection might hang in the connecting state or fail to establish after the first unsuccessful attempt. In some cases, repeated attempts produced the error The specified port is already in use.
• Storage Spaces. Fixed an issue with Storage Spaces Direct virtual disks that use storage tiers. After installing certain security updates, some virtual disks might fail to come online, making dependent cluster workloads unavailable.
• Date and time. Added a new time zone, (UTC-05:00) Manitoba, to support the time zone change in Manitoba on November 1, 2026.
• ReFS security. Auditing and additional policy-based controls have been added for ReFS volumes on external drives. Auditing is enabled by default, while enforcement of restrictions is disabled so that administrators can evaluate upcoming security hardening changes and prepare for them.
• Printing. Fixed an issue where, after installing the August 2026 security update, printing might not work in some apps and on devices with RAW or Generic Text Only printer drivers.
• Gaming. Fixed an issue that could cause intermittent mouse input processing in some games.
• Windows Hello. Fixed an issue where, on some devices, fingerprint sign-in might not work after turning on the computer from a fully powered-off state.
• Known issue: USB Audio Class 1.0. After installing KB5124012, some USB Audio Class 1.0 devices may stop playing sound. The error This device cannot start (Code 10), volume control failures, and unavailable sound settings are possible. Update KB5129195 fixes failures in eight-channel mode and 3D audio mode, but the other manifestations of the issue persist for now. In some cases, switching to two-channel mode helps. Microsoft is working on a complete fix.

Cumulative update KB5127648 installs automatically on PCs through Windows Update. To check, go to Settings > Windows Update and click Check for updates.

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