Windows 11 KB5127648 & KB5127646 October 2026 Patch Tuesday Released

Microsoft has released its October 2026 Patch Tuesday updates for Windows 11. The KB5127648 update covers versions 24H2, 25H2, and 26H2, with new OS builds addressing Explorer crashes, audio playback, VPN connectivity, and gaming issues.

Windows 11 October 2026 Patch Tuesday update KB5127648 fixes Explorer crashes, gaming stutter, and more

The October 2026 Patch KB5127648 bumps Windows 11 version 26H2 to build 26300.9711, version 25H2 to build 26200.9711, and version 24H2 to build 26100.9711. The update addresses Windows Explorer crashes in multi-user environments. On affected Azure Virtual Desktop and FSLogix systems, Explorer.exe could fail to start after sign-in or repeatedly crash, leaving users with a black screen. Microsoft has also fixed an AC-3 audio playback issue affecting some applications.

Gaming gets attention, too. The update fixes an issue that could cause mouse input to stutter in some games. Windows Hello fingerprint sign-in problems following a cold boot are also addressed.

Meanwhile, Microsoft has resolved an Always On VPN issue introduced after installing KB5124008. Affected connections could remain stuck on Connecting or fail after an initial connection attempt. Some users also encountered a “The specified port is already in use” error.

More security, printing, and time zone improvements

The October Patch Tuesday release continues Microsoft’s rollout of updated Secure Boot certificates. Windows Update uses updated targeting data to identify eligible devices ready to receive them automatically.

Microsoft has also fixed a printing problem affecting some applications and devices using RAW or Generic Text Only printer drivers. The issue appeared after installing the August 2026 security update.

Another change introduces the new UTC-05:00 Manitoba time zone ahead of the region’s November 1, 2026, time zone change. For storage environments, the update fixes certain Storage Spaces Direct virtual disks that could fail to come online after security updates.

The update adds auditing and optional policy controls for ReFS volumes on externally attached storage devices. Auditing is enabled by default, while enforcement remains disabled by default to give administrators time to prepare.

Windows 11 26H1 gets security update under KB5127646

Windows 11 version 26H1 also receives the October 2026 Patch Tuesday update under KB5127646 (OS Build 28000.3231). You can check key fixes and improvements below:

• [Security updates] This update provides security improvements. For more information about the security vulnerabilities resolved by this update.
• [Secure Boot] This update includes additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Certificate deployment via Windows updates continues across supported PCs and non-managed business devices in the coming months.
• [ReFS security] This update adds auditing and optional policy controls for ReFS volumes on externally attached storage devices. Auditing is enabled by default, while enforcement controls remain disabled by default to give administrators time to evaluate and prepare for future security hardening changes.
• [Windows Explorer (Known issue)] Fixed This update fixes an issue that affects Windows Explorer in multi-user environments, such as Azure Virtual Desktop and FSLogix. After sign-in, Explorer.exe might fail to start or repeatedly crash, causing a black screen.
• [Always On VPN] This update fixes an issue that affect Always On VPN connections after installing KB5124008. When automatic protocol selection or protocol fallback was configured, affected VPN connections could remain stuck in a Connecting state or fail to connect after an initial connection attempt failed. In some cases, subsequent connection attempts could display the error, “The specified port is already in use.”
• [Storage Spaces Direct] This update fixes an issue that affects tiered Storage Spaces Direct virtual disks. Some virtual disks might fail to come online after installing certain security updates, making dependent clustered workloads unavailable.
• [Gaming] This update resolves an issue that could cause mouse input to stutter in some games.

You can download and install these updates via Windows Update settings or Microsoft Update Catalog (KB5127646 and KB5127648).