Windows 11 cumulative updates KB5124008 & KB5122880 released

Microsoft has released Windows 11 KB5124008 and KB5122880 cumulative updates for versions 25H2/24H2 and 23H2 to fix security vulnerabilities, bugs, and add new features.

Today's updates are mandatory as they contain the September 2026 Patch Tuesday security patches for 1,000 vulnerabilities discovered in previous months.

You can install today's update by going to Start > Settings > Windows Update and clicking on 'Check for Updates.'

You can also manually download and install the update from the Microsoft Update Catalog.

This is the ninth 'Patch Tuesday' release in 2026, and it's based on 24H2, which means 25H2 gets the same update. There are no exclusive or special changes. You'll get the same fixes across the two versions of Windows 11.

What's new in the September 2026 Patch Tuesday update

With today's update, Microsoft added a movable taskbar, Windows Search without Bing, and more.

Here's the full list of improvements and fixes:

Taskbar

• This update gives you more ways to customize the taskbar to match how you work and make better use of screen space.

  • New! You can now choose whether the taskbar appears at the bottom, top, left, or right side of your screen. In these other positions, tooltips, flyouts, and animations will still come from the taskbar, and most customization settings, such as never combining taskbar icons, will work with all locations. Search box and smaller taskbar are currently supported only for top and bottom positions. To change the position of the taskbar, go to Settings > Personalization > Taskbar > Taskbar behaviors > Taskbar position

  • New! A smaller taskbar option is now available to help maximize screen space on smaller devices. This experience reduces the size of taskbar icons and the taskbar height while maintaining access to key features such as Start, Search, and the system tray. To change your taskbar size, go to Settings > Personalization > Taskbar > Taskbar behaviors > Taskbar size. When set to Small, both the icons and the taskbar height become smaller.

  • New! The Taskbar behaviors section of the Taskbar settings page is now expanded by default for improved discoverability.

• This update improves reliability of loading the system tray area of the taskbar for non-touch PCs.

• This update makes the Start menu more personal with several customizations.

  • New! You can choose between a small or large Start menu, in addition to "Automatic (default)" that's available today. To customize this, go to Settings > Personalize > Start > Start menu size.

  • New! The "Recommended" section is renamed "Recent" in the Start menu and Settings page (Settings > Personalize > Start).

  • New! You can now hide your name and profile picture in Start by going to Settings > Personalize > Start > Hide your name and profile picture on Start.

  • New! The Start menu settings page is now redesigned with section-level toggles to independently show or hide Pinned, Recommended, and All.

Windows Search

• This update includes improvements that make Windows Search more dependable, easier to scan, and clearer before you click.

  • New! Search home has been simplified to reduce visual clutter and make it easier to get back to recent searches quickly.

  • New! Search does a better job showing where a result comes from—app, setting, file, web result, or Store suggestion—so it’s easier to tell what you’re looking at and where you will go before you click.

  • New! A new setting in Settings > Privacy & Security > Search lets you choose whether web and Microsoft Store suggestions appear alongside local results.

  • New! Windows now automatically indexes your most used folders to make those files appear in subsequent search results. You can control the setting at Settings > Privacy & Security > Search > Automatically find additional relevant locations

File Explorer

• New! Launching File Explorer Home is now faster and more responsive.

• New! The Recommended section on Home now supports touch scrolling, making it easier to browse files in the carousel.

General design

• New! This update introduces updated progress indicators across Windows, providing a more consistent and modern experience during startup, sign-in, restart, shutdown, and update installation.

• New! This update adds the ability for users signed in with a work or school account to discover and install relevant apps directly from the share window. To manage this experience, go to Settings > System > Share and select Show suggested apps in share surfaces.

Administrator Protection

• New! Administrator protection aims to protect free floating admin rights for administrators. It enables users to perform administrative tasks using just-in-time privileges. Administrator protection is not classified as a formal security boundary; it hardens the security against elevation-of-privilege attacks with the introduction of profile separation. This feature is turned off by default and can be enabled using OMA-URI in Microsoft Intune or through Group Policy. This feature was previously disclosed in October 2025 (KB5067036) and is now beginning to roll out.

Multiple desktops

• Switching between virtual desktops is now smoother and more responsive.

Display and Graphics

• This update improves the reliability of navigating to and interacting with Settings > System > Display.

• This update improves the persistence of previous brightness settings once the energy saver turns off.

Task Manager

• This update improves the reliability of displaying app history information in Task Manager.

Windows Setup

• This update streamlines the experience for selecting a secondary keyboard during Windows setup, making it easier to skip when it isn't needed.

• This update improves the Get Started app with new App install, Site pinning, and Theme pages to help you personalize your device and discover new features.

Windows Update

• This update improves restart behavior so PCs that were manually put to sleep return to sleep after completing an update, even when automatic sleep is set to Never.

App updates

• This update adds support for participating apps to coordinate their updates with Windows Update. Supported apps can benefit from improved scheduling and a more streamlined update experience. For more information, see Windows Update Orchestration Platform (UOP).

Microsoft store

• New! This update provides support for in-app purchases in packaged WinUI 3 apps that require elevation, helping developers offer purchases through Microsoft's integrated commerce platform.

Windows Autopilot device preparation

• New! Device association for Windows Autopilot device preparation is now generally available. This feature helps organizations identify trusted devices before enrollment, enabling device-targeted policies, automatic corporate device enrollment, and additional setup customization during the out-of-box experience (OOBE). To learn more, see Windows Autopilot device preparation.

Microsoft Execution Containers

• New! This update introduces Process Isolation for Microsoft Execution Containers (MXC), a fast, lightweight boundary for responsive workloads such as coding agents and model-generated code. It uses Windows operating-system containment capabilities to restrict access to resources such as files, networking, the user interface, and other operating-system capabilities according to policy.

Agentic processes

• New! This update introduces preview platform support for tagging agentic processes. Authorized components can assign an opaque agent identifier to a process token. Windows protects the marking and automatically passes it to child processes. When an agentic process authenticates through Web Account Manager (WAM), WAM includes the agent identifier from the process token in the authentication request. As a preview capability, the identifier format may change in future releases.

Microsoft is not aware of any new issues with this month's Patch Tuesday, but we'll update the article if we come across major problems.