What's new in KB5089549 (Windows 11 build 26200.8457)
- Windows 11 version 25H2 (Build 26200.8457)
- Windows 11 version 24H2 (Build 26100.8457)
Priya Natarajan3 min readQuick answer
KB5089549 is a mandatory cumulative security update released on May 12, 2026, for Windows 11 version 24H2 and version 25H2. It updates your system build to OS Build 26200.8457 (or OS Build 26100.8457) and delivers important security fixes and platform maintenance. You can install it automatically through Windows Update or download it manually from the Microsoft Update Catalog.
Microsoft released update KB5089549 on May 12, 2026, as a mandatory cumulative update for devices running Windows 11 version 24H2 and Windows 11 version 25H2. Depending on which release version of Windows 11 is installed on your computer, applying this patch updates your operating system build revision to OS Build 26200.8457 for version 25H2 systems or OS Build 26100.8457 for version 24H2 systems.
Because KB5089549 arrives as part of Microsoft's regular Patch Tuesday release cycle, it includes critical security enhancements, background maintenance, and core component fixes aimed at preserving overall system integrity. Whether you use your PC for daily work, gaming, or general personal use, staying current with mandatory monthly updates helps keep your operating system secure against newly identified vulnerabilities.
Highlights
- OS Build 26200.8457 release: Advances Windows 11 version 25H2 systems to OS Build 26200.8457 to deliver May 12, 2026 security updates.
- OS Build 26100.8457 release: Updates Windows 11 version 24H2 systems to OS Build 26100.8457 with refreshed core binaries.
- Cumulative security updates: Incorporates monthly Patch Tuesday security protections across Windows core OS components.
- Dual-version alignment: Synchronizes release updates simultaneously for both Windows 11 version 24H2 and version 25H2 servicing channels.
- Servicing stack improvements: Upgrades internal servicing components to ensure future updates download and install reliably.
Known issues
Microsoft reports no known issues for this update.
Should you install it?
Yes, you should install KB5089549 on your PC. Because KB5089549 is a mandatory monthly security update rather than an optional preview update, Microsoft automatically distributes it to protect systems from known security risks. Delaying or skipping mandatory updates leaves your device exposed to unpatched software vulnerabilities.
For most users, Windows Update will handle the download and installation process automatically during non-active hours. However, if you rely on your machine for mission-critical tasks, ensuring you have a recent system backup or restoring point before initiating any operating system restart remains a good practice.
How to get it
Illustration: the About page under Settings > System
To check for and install KB5089549 using the default Windows Update tool, follow these steps:
- Go to Settings > Windows Update on your PC.
- Click the Check for updates button on the right panel.
- Wait while Windows Update checks for available updates; KB5089549 will begin downloading automatically.
- Click the Restart now button once the download and initial installation phase complete.
If you want to confirm your installed build revision after restarting, check the Settings app:
- Go to Settings > System > About.
- Scroll down to the Windows specifications section.
- Verify that your OS build matches either 26200.8457 or 26100.8457.
Alternatively, advanced users can check their build using system utilities:
- Press Windows key + R, type winver, and press Enter to view the Windows version window.
- Open PowerShell as administrator and run Get-ComputerInfo | Select-Object WindowsVersion, OsBuildNumber to print build information. Caution: Always exercise caution when running elevated command-line tools to avoid unintended configuration changes.
If Windows Update experiences delays or fails to finish, you can manually download the update package directly from the Microsoft Update Catalog:
- Open your internet browser and visit the official Microsoft Update Catalog website.
- Search for KB5089549 in the search bar located in the upper right corner.
- Locate the correct download entry matching your Windows 11 version (version 24H2 for OS Build 26100.8457 or version 25H2 for OS Build 26200.8457) and device processor architecture (x64 or ARM64).
- Click Download next to the matching entry, and select the resulting file link to save the standalone .msu installer package to your storage drive.
- Double-click the downloaded .msu file to launch the standalone installer and follow the wizard instructions to finish installing KB5089549.
Sources
Frequently asked questions
What is KB5089549?
KB5089549 is a mandatory Patch Tuesday security update released by Microsoft on May 12, 2026, for Windows 11 version 24H2 and version 25H2.
Which build numbers are associated with KB5089549?
KB5089549 updates Windows 11 version 25H2 to OS Build 26200.8457 and Windows 11 version 24H2 to OS Build 26100.8457.
Do I need to install KB5089549 manually?
No, Windows Update will automatically download and install KB5089549. However, you can also manually install it using standalone packages from the Microsoft Update Catalog.
Are there any known issues with KB5089549?
Microsoft reports no known issues for this update.
Checked against Microsoft's release notes on ; re-checked when a new build ships.
Writes Thea's how-to guides for new and changed Windows 11 features: where a setting moved, how to turn it on or off, and what it actually does. Every guide is checked against Microsoft's release notes and updated when a new build changes the steps.
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