Windows 11 KB5089549: What’s New in the May 2026 Update

On Tuesday, May 12, 2026, Microsoft released the new cumulative updates for Windows 11: KB5089549 and KB5087420. What are the main changes? Here’s everything you need to know!

• Windows 10 KB5087544 - May 2026 Update

Reminder: the May 2026 Patch Tuesday fixes 120 vulnerabilities across Microsoft products, including Windows. This update therefore helps remediate vulnerabilities in addition to the changes mentioned below.

Depending on the Windows 11 version you are using, the KB you need to install is not the same:

• The KB5087420 is intended for Windows 11 25H2 and Windows 11 24H2,
• The KB5087420 is available for Windows 11 23H2.

The main changes in Windows 11

👉 BitLocker - Fix for a known issue

This update fixes an issue that could cause some devices to enter BitLocker recovery mode after boot files were updated on certain devices. This is a known issue that appeared after the installation of the April 2026 updates (including KB5083769) and only affects certain invalid configurations (with PCR7).

Microsoft also explains that this update improves boot reliability after boot file updates, which should prevent some inconveniences, especially the BitLocker recovery screen.

👉 Many improvements included in this update

Most importantly, this new update includes many of the improvements already introduced by KB5083631, released on April 30, 2026. As a reminder, that update lets you test new features before the mandatory release, which this month is KB5089549.

These include:

• The arrival of Xbox mode,
• Support for new archive formats in File Explorer: uu, cpio, xar and NuGet (nupkg),
• Microsoft has introduced a new method to harden Batch file processing (CMD scripts). Running these scripts can expose attack vectors if the file is modified while it is executing. To address this issue, Microsoft introduced a new Registry setting called LockBatchFilesWhenInUse.
• This update adds support for a custom list to define which preinstalled apps should be removed, either through Group Policy or Microsoft Intune (final integration of a feature unveiled last March).
• And more...

To learn everything about the new features, I invite you to read this article: the new features in KB5083631 for Windows 11.

Windows 11: May 2026 KBs

Below is the list of May 2026 updates for Windows 11.

• Windows 11 24H2 and Windows 11 25H2 : KB5089549
• Windows 11 23H2 : KB5087420
• Windows 11 21H2 : end of support

These updates are available now through the usual channels, starting with Windows Update.

Windows 11 updates for 2026

Below is a summary of the mandatory updates released in 2026 for the different Windows 11 versions.

Florian Burnel Co-founder of IT-Connect

Systems and network engineer, co-founder of IT-Connect and Microsoft MVP "Cloud and Datacenter Management". I'd like to share my experience and discoveries through my articles. I'm a generalist with a particular interest in Microsoft solutions and scripting. Enjoy your reading.

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