May 12, 2026—KB5089549 (OS Builds 26200.8457 and 26100.8457)
Applies To
Release Date:
5/12/2026
Version:
OS Builds 26200.8457 and 26100.8457
This cumulative update for Windows 11, version 25H2 and 24H2 (KB5089549) includes the latest security fixes and improvements, along with non-security updates from last month's optional preview release.
Visit the Windows release health dashboard for the latest status on this release.
Announcements and messages
This section provides key notifications related to this release, including announcements, change logs, and end-of-support notices.
Windows Secure Boot certificate expiration
Important: Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. This might affect the ability of certain personal and business devices to boot securely if not updated in time. To avoid disruption, we recommend reviewing the guidance and taking action to update certificates in advance. For details and preparation steps, see Windows Secure Boot certificate expiration and CA updates.
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Change date |
Change description |
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May 15, 2026 |
Know issue added: "May 2026 security update fails to install with error 0x800f0922" |
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May 13, 2026 |
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Improvements
This update includes new features and quality improvements that were part of the following update:
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April 14, 2026—KB5083769 (OS Builds 26200.8246 and 26100.8246)
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April 30, 2026—KB5083631 (OS Builds 26200.8328 and 26100.8328) Preview
This update addresses security vulnerabilities documented in the following guide:
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May 2026 Security Updates
The following summary outlines key quality improvements addressed by this update. The bold text within the brackets indicates the item or area of the change.
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[Secure Boot]
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With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Devices receive the new certificates only after demonstrating sufficient successful update signals, maintaining a controlled and phased rollout.
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This update adds a new SecureBoot folder under C:\Windows on eligible devices. The folder contains example scripts intended for organizations with IT professionals who actively manage updates across their device fleet. These scripts can be used to detect Secure Boot certificate update status and automate deployment via a safe rollout mechanism in an Active Directory environment. For more information, see Sample Secure Boot E2E Automation Guide.
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[Boot manager servicing update]
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This update improves startup reliability after boot file updates, so devices start normally without entering BitLocker recovery.
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(Known issue) Fixed: This update addresses an issue where some devices might enter BitLocker Recovery after updating boot files on systems with certain Trusted Platform Module (TPM) validation settings, including invalid PCR7 (Platform Configuration Register 7) configurations. This might occur after installing the April 2026 security update (KB5083769).
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[Connectivity] This update improves the reliability of Simple Service Discovery Protocol (SSDP) notifications to help prevent the service from becoming unresponsive.
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[Daylight saving time (DST)] This update supports the 2023 DST change for the Arab Republic of Egypt.
If you've already installed previous updates, your device will download and install only the new updates included in this package.
AI Components
This release updates the following AI components:
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AI Component |
Version |
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Image Search |
1.2604.515.0 |
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Content Extraction |
1.2604.515.0 |
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Semantic Analysis |
1.2604.515.0 |
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Settings Model |
1.2604.515.0 |
Windows 11 servicing stack update (KB5092762)- 26100.8456
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates. To learn more about SSUs, see Simplifying on-premises deployment of servicing stack updates.
Known issues in this update
Symptoms
After you install this update (KB5089549), some devices might fail to complete installation with error code 0x800f0922. This issue occurs on devices that have limited free space on the EFI System Partition (ESP), especially if it has 10 MB or less available.
What you might experience on affected devices:
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The update installs successfully during the initial phases.
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The installation fails during the restart phase at approximately 35–36% completion.
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Windows then rolls back the update.
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You may see the message: “Something didn’t go as planned. Undoing changes.”
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The installation fails with error code 0x800f0922.
As a result of this issue, you might see log entries similar to the following in C:\Windows\Logs\CBS\CBS.log, indicating insufficient free space on the EFI System Partition:
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SpaceCheck: Insufficient free space
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ServicingBootFiles failed. Error = 0x70
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SpaceCheck: <value> used by third-party/OEM files outside of Microsoft boot directories
Workaround
Affected customers can use one of the following workarounds to mitigate this issue.
Option 1: Allow the update to install by modifying an ESP registry setting
Important: Editing the registry incorrectly can cause serious system problems. Always back up the registry before making any changes.
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Open Command Prompt as an administrator.
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Run the following command: reg add “HKLM\SYSTEM\CurrentControlSet\Control\Bfsvc /v EspPaddingPercent /t REG_DWORD /d 0 /f”
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Restart the affected device.
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Retry installing the update.
Option 2: Mitigate the issue by using Known Issue Rollback (KIR)
This issue is mitigated using Known Issue Rollback (KIR). The resolution has already propagated automatically to consumer devices and non‑managed business devices. Restarting your Windows device might help the resolution apply more quickly.
Enterprise-managed devices
For devices where Windows updates are managed by IT departments, administrators can apply the mitigation by installing and configuring a special Group Policy. You can find the policy at Computer Configuration > Administrative Templates > <Group Policy name listed below>.
Group Policy download
Windows 11, version 25H2 and Windows 11, version 24H2: KB5089549 260514_06221 Known Issue Rollback
Important: You must install and configure the Group Policy that matches your version of Windows to resolve this issue. You must also restart affected devices to apply the policy. This Group Policy temporarily disables the change that causes the issue.
For more information, seeHow to use Group Policy to deploy a Known Issue Rollback.
A resolution is in progress and will be included in a future Windows update. This documentation will be updated once the resolution is available.
How to get this update
Before you install this update
Microsoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates.
Install this update
To install this update, use one of the following Windows and Microsoft release channels.
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Available |
Next Step |
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This update downloads and installs automatically from Windows Update and Microsoft Update. |
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Available |
Next Step |
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This update downloads and installs automatically from Windows Update for Business in accordance with configured policies. |
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Available |
Next Step |
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To install this release from the Microsoft Update Catalog, select the option that matches your device architecture (arm64 or x64), and then follow the instructions. |
Before you install this update, the standalone package(s) for this update is available from the Microsoft Update Catalog website. This KB contains one or more MSU files that require installation in a specific order.
You can install this update using Method 1 (install all MSU files together) or Method 2 (install each MSU file individually, in order).
Method 1: Install all MSU files together
Download all MSU files for KB5089549 from Microsoft Update Catalog and place them in the same folder (for example, C:/Packages). Use Deployment Image Servicing and Management (DISM.exe) to install the target update. DISM will use the folder specified in PackagePath to discover and install one or more prerequisite MSU files as needed.
Updating Windows PC
To apply this update to a running Windows PC, run the following command from an elevated Command Prompt:
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DISM /Online /Add-Package /PackagePath:c:\packages\windows11.0-kb5089549-arm64_937a22a527bc406da7306b7b8cc6f2448909f55d.msu |
Or, run the following command from an elevated Windows PowerShell prompt:
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Add-WindowsPackage -Online -PackagePath "c:\packages\windows11.0-kb5089549-arm64_937a22a527bc406da7306b7b8cc6f2448909f55d.msu " |
Or use Windows Update Standalone Installer to install the target update.
Updating Windows Installation media
To apply this update to Windows Installation media, see Update Windows installation media with Dynamic Update.
Note: When downloading other Dynamic Update packages, ensure they match the same month as this KB. If the SafeOS Dynamic Update or Setup Dynamic Update is not available for the same month as this KB, use the most recently published version of each.
To add this update to a mounted image, run the following command from an elevated Command Prompt:
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DISM /Image:mountdir /Add-Package /PackagePath:Windows11.0-kb5089549-arm64_937a22a527bc406da7306b7b8cc6f2448909f55d.msu |
Or, run the following command from an elevated Windows PowerShell prompt:
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Add-WindowsPackage -Path "c:\offline" -PackagePath "Windows11.0-kb5089549-arm64_937a22a527bc406da7306b7b8cc6f2448909f55d.msu" -PreventPending |
Method 2: Install each MSU file individually, in order
Download and install each MSU file individually either using DISM or Windows Update Standalone Installer in the following order:
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windows11.0-kb5043080-arm64_df540a05f9b118e339c5520f4090bb5d450f090b.msu
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windows11.0-kb5089549-arm64_937a22a527bc406da7306b7b8cc6f2448909f55d.msu
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Note: This latest cumulative update includes updates for AI components. Even though the AI component updates are included in the update, the AI components are only applicable to Windows Copilot+ PCs and will not install on Windows PC or Windows Server. |
Before you install this update, the standalone package(s) for this update is available from the Microsoft Update Catalog website. This KB contains one or more MSU files that require installation in a specific order.
You can install this update using Method 1 (install all MSU files together) or Method 2 (install each MSU file individually, in order).
Method 1: Install all MSU files together
Download all MSU files for KB5089549 from Microsoft Update Catalog and place them in the same folder (for example, C:/Packages). Use Deployment Image Servicing and Management (DISM.exe) to install the target update. DISM will use the folder specified in PackagePath to discover and install one or more prerequisite MSU files as needed.
Updating Windows PC
To apply this update to a running Windows PC, run the following command from an elevated Command Prompt:
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DISM /Online /Add-Package /PackagePath:c:\packages\windows11.0-kb5089549-x64_9a542b5813b003374532dceeba49b7e07c3fc2fb.msu |
Or, run the following command from an elevated Windows PowerShell prompt:
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Add-WindowsPackage -Online -PackagePath "c:\packages\windows11.0-kb5089549-x64_9a542b5813b003374532dceeba49b7e07c3fc2fb.msu " |
Or use Windows Update Standalone Installer to install the target update.
Updating Windows Installation media
To apply this update to Windows Installation media, see Update Windows installation Media with Dynamic Update.
Note: When downloading other Dynamic Update packages, ensure they match the same month as this KB. If the SafeOS Dynamic Update or Setup Dynamic Update is not available for the same month as this KB, use the most recently published version of each.
To add this update to a mounted image, run the following command from an elevated Command Prompt:
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DISM /Image:mountdir /Add-Package /PackagePath:windows11.0-kb5089549-x64_9a542b5813b003374532dceeba49b7e07c3fc2fb.msu |
Or, run the following command from an elevated Windows PowerShell prompt:
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Add-WindowsPackage -Path "c:\offline" -PackagePath "windows11.0-kb5089549-x64_9a542b5813b003374532dceeba49b7e07c3fc2fb.msu" -PreventPending |
Method 2: Install each MSU file individually, in order
Download and install each MSU file individually either using DISM or Windows Update Standalone Installer in the following order:
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windows11.0-kb5043080-x64_953449672073f8fb99badb4cc6d5d7849b9c83e8.msu
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windows11.0-kb5089549-x64_9a542b5813b003374532dceeba49b7e07c3fc2fb.msu
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Note: This latest cumulative update includes updates for AI components. Even though the AI component updates are included in the update, the AI components are only applicable to Windows Copilot+ PCs and will not install on Windows PC or Windows Server. |
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Available |
Next Step |
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This update automatically syncs with Windows Server Update Services (WSUS) if you configure Products and Classifications as follows: Product: Windows 11 Classification: Security Updates |
If you want to remove this update
Before you decide to remove this update, see Understanding the risks: Why you should not uninstall security updates.
To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.
Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.
File information
For a list of the files provided in this update, download the file information for cumulative update 5089549.
For a list of the files provided in the servicing stack update, download the file information for the SSU (KB5092762) - version 26100.8456.
Related topics
Windows monthly updates explained
Description of the standard terminology used for Microsoft software updates
Microsoft Store for Business and Education with Configuration Manager
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