Windows 11 KB5089573 Fixes Patch Tuesday Errors

Critical Patch Tuesday Issue Resolved

The issue originated with the May 2026 security update (KB5089549), which caused installation failures on affected Windows 11 systems. Users encountered the error code 0x800f0922, with the installation process stopping during the reboot phase at approximately 35–36% completion.

Microsoft identified the root cause as insufficient free space on the EFI System Partition (ESP), particularly on devices with 10 MB or less available storage in the partition. This left many enterprise and consumer devices unable to successfully install important security updates.

To mitigate the issue, Microsoft initially deployed a Known Issue Rollback (KIR) and provided enterprise administrators with a registry-based workaround involving modifications to the EspPaddingPercent value. However, these measures were temporary solutions.

With the release of KB5089573, Microsoft has now delivered a permanent fix, eliminating the need for previous workarounds and ensuring smoother update deployments moving forward.

What's New in KB5089573?

In addition to resolving the ESP-related installation failure, KB5089573 includes several enhancements designed to improve Windows 11 performance, reliability, and future update readiness.

AI Component Enhancements

Microsoft continues expanding AI-powered experiences across Windows 11 with updated components, including:

Image Search;Content Extraction;Semantic Analysis;Settings Model

All AI components have been upgraded to version 1.2605.856.0, bringing improved intelligence and responsiveness to supported Windows features.

Servicing Stack Update (KB5092734)

The package also includes Servicing Stack Update (SSU) KB5092734 (Build 26100.8519), which strengthens the Windows Update infrastructure and improves the reliability of future update installations.

Known Issues and Uninstallation Guidance

Microsoft has confirmed that no known issues currently affect KB5089573.

If administrators need to identify installed packages, Microsoft recommends using:

DISM /online /get-packages

For removal scenarios, the package must be handled using the appropriate DISM Remove-Package commands. Microsoft notes that uninstalling the update through:

wusa.exe /uninstall

is not supported because the cumulative package contains a Servicing Stack Update (SSU), which cannot be removed independently once installed.

Microsoft strongly advises against uninstalling security updates unless absolutely necessary, as doing so may expose systems to known vulnerabilities.

Why This Update Matters

For organizations managing large Windows environments, update reliability is essential for maintaining cybersecurity posture and regulatory compliance. The EFI System Partition issue impacted a significant number of systems, delaying critical security patch deployment and increasing operational risk.

KB5089573 not only resolves the installation failure but also strengthens Windows Update reliability, enhances AI-powered capabilities, and ensures devices remain protected against emerging security threats.