Microsoft Windows 11 25H2 Update Version OS Builds 26200.8457 and 26100.8457

KB5089549 updates Windows 11 version 25H2 and 24H2 to OS Builds 26200.8457 and 26100.8457. It includes May 2026 security fixes, Secure Boot certificate rollout improvements, boot reliability fixes, DST support for Egypt, and a known install issue on low-space EFI partitions. Reference IDs: KB5083769, KB5083631, KB5092762, KB5089573.

• Includes the latest May 2026 security fixes and addresses vulnerabilities documented in the May 2026 Security Updates guide.
• Improves Secure Boot certificate targeting and rollout for eligible devices to support upcoming certificate updates.
• Adds a new C:\Windows\SecureBoot folder on eligible devices with scripts for Secure Boot certificate status detection and automated deployment.

• Improves startup reliability after boot file updates and helps prevent BitLocker recovery on affected systems.
• Fixes an issue where some devices could enter BitLocker Recovery after boot file updates with certain TPM validation settings, including invalid PCR7 configurations.
• Improves the reliability of SSDP notifications to help prevent the service from becoming unresponsive.
• Adds support for the 2023 DST change for the Arab Republic of Egypt.

• Adds a new C:\Windows\SecureBoot folder on eligible devices containing example scripts for Secure Boot certificate management.
• Introduces additional high-confidence device targeting data to expand automatic Secure Boot certificate coverage.

• Some devices may fail to install the update with error 0x800f0922 when the EFI System Partition has very limited free space, especially 10 MB or less.
• Affected installations may roll back during restart at about 35–36% completion and show "Something didn’t go as planned. Undoing changes."
• The issue is addressed in KB5089573.

• This cumulative update includes non-security updates from the April 30, 2026 preview release KB5083631 and quality improvements from KB5083769.
• A servicing stack update is included: KB5092762 for OS Build 26100.8456.
• Microsoft warns that Secure Boot certificates used by most Windows devices begin expiring in June 2026; administrators should review the certificate update guidance in advance.
• If previous updates are already installed, only the new changes in this package will be downloaded and installed.

• KB5089549 release notes
  https://support.microsoft.com/help/5089549
• Workaround update for the install issue
  https://support.microsoft.com/help/5089573
• Servicing stack update KB5092762
  https://support.microsoft.com/help/5092762

Product Information

Vendor: Microsoft

Product: Windows 11

Version: OS Builds 26200.8457 and 26100.8457

Release date: May 12, 2026