Microsoft Patches Windows 11 Update KB5089573 Installation Issues

Key Takeaways

• Microsoft has released cumulative update KB5089573 to fix a significant installation error affecting Windows 11 versions 25H2 and 24H2.
• The previous May 2026 Patch Tuesday update (KB5089549) failed on systems with 10 MB or less free space on the EFI System Partition (ESP), leading to installation crashes.
• KB5089573 permanently resolves the installation failure, eliminating the need for prior workarounds.
• The update also brings AI component refreshes, personalization improvements, and a Servicing Stack Update (SSU) to enhance future update reliability.

Microsoft Addresses Critical Windows 11 Update Installation Failures with KB5089573

Microsoft has deployed a crucial cumulative update, KB5089573, for Windows 11 versions 25H2 and 24H2. This update specifically targets and resolves a critical installation problem that emerged after the May 2026 Patch Tuesday rollout, preventing many users from successfully updating their systems.

The new update advances the operating system builds to 26200.8524 and 26100.8524, respectively. Its primary function is to rectify a widely reported error that caused numerous systems to halt during the monthly security update process.

Understanding the May 2026 Patch Tuesday Issue

The May 2026 Patch Tuesday security update, identified as KB5089549, triggered installation failures on a specific subset of Windows 11 devices. Users encountered error code 0x800f0922, which brought the update process to a standstill.

This particular failure predominantly affected devices with critically low free space on their EFI System Partition (ESP), specifically those with 10 MB or less available. Systems impacted by this bug would proceed through the initial stages of installation but then crash during the reboot phase, typically at around 35–36% completion. This left affected devices in an unstable and inconsistent state.

Prior to this permanent fix, Microsoft had offered temporary solutions. One was a Known Issue Rollback (KIR), which automatically provided relief to consumer and unmanaged business devices. Additionally, enterprise administrators had access to a registry-based workaround involving the modification of the EspPaddingPercent value under HKLMSYSTEMCurrentControlSetControlBfsvc. However, the release of KB5089573 on May 26, 2026, renders both previous workarounds unnecessary by providing a definitive resolution.

KB5089573: More Than Just a Fix

Beyond addressing the critical ESP space issue, KB5089573 is a comprehensive cumulative update. It is being delivered in two phases: an initial gradual rollout for staged device delivery, followed by a normal rollout for broader general availability. This update integrates several important enhancements:

• AI Component Refresh: Key AI components such as Image Search, Content Extraction, Semantic Analysis, and the Settings Model have all been updated to version 1.2605.856.0. This reflects Microsoft’s ongoing efforts to enhance on-device AI capabilities within Windows 11.
• Personalization Improvements: New personalization features were incorporated on May 28, 2026, as part of the gradual deployment phase.
• Servicing Stack Update (KB5092734): This update, bringing the build to 26100.8519, specifically improves the reliability and robustness of the Windows update installation infrastructure itself. This ensures that devices can receive future patches more cleanly and efficiently.

The update is accessible through various channels and has no prerequisites beyond a compatible Windows 11 25H2 or 24H2 device.

Installation and Management

Users can obtain and install KB5089573 through the following methods:

1. Navigate to Start → Settings → Windows Update → Advanced options → Optional updates.
2. Select the available update and click “Download and Install.”
3. Alternatively, download the standalone package directly from the Microsoft Update Catalog using the KB number.
4. For enterprise environments, deployment is available via Windows Update for Business or WSUS.

Microsoft has confirmed that, as of its release, KB5089573 has no known issues.

Should removal of the update become necessary, Microsoft advises using the DISM /online /get-packages command to identify the specific package name. Following this, the DISM/Remove-Package option, with the LCU package name as the argument, can be used. It is important to note that attempting to uninstall using the Windows Update Standalone Installer (wusa.exe) with the /uninstall switch will not work, as this combined package includes a Servicing Stack Update (SSU), which cannot be removed after installation. Microsoft strongly cautions against removing security updates due to the inherent risks this poses to system security.

What You Should Do

• Prioritize Installation: Given the critical nature of the ESP space issue, which impacted a significant number of both enterprise and consumer devices, IT administrators and end-users should prioritize the installation of KB5089573 during their next maintenance window.
• Verify Free Space (Pre-emptively): While the patch fixes the issue, regularly monitoring and ensuring adequate free space on the EFI System Partition (ESP) is a good practice to prevent future update complications.
• Utilize Official Channels: Always obtain updates directly through Windows Update or the Microsoft Update Catalog to ensure authenticity and integrity.
• Do Not Remove Security Updates: Microsoft strongly advises against uninstalling security updates due to the increased vulnerability exposure.

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