Microsoft has fixed a known issue that caused installation failures and 0x800f0922 errors when deploying the May 26, 2026, Windows 11 security update KB5089549.
The fix is included in the KB5089573 preview cumulative update released on May 26 and will be available to all users via the June Patch Tuesday update later this month.
The failures were due to insufficient free space on the EFI system partition (ESP), which caused the update to be automatically rolled back on affected devices.
What caused KB5089549 install failures and how to fix them
Microsoft confirmed two weeks ago that the issue affected devices with limited free space on the EFI system partition, particularly those with 10MB or less available. On these systems, the installation process will start normally but will fail during the reboot phase when it is approximately 35 to 36 percent complete.
When the update came back out, affected users saw a message saying, “Something didn’t go as planned. Changes are being undone.” The logs of the affected systems included entries such as “spacecheck” and “servicingbootfiles failed”, which pointed to insufficient free space on the EFI system partition.
Microsoft says the issue has been fixed with the update released May 26, 2026 (KB5089573) and later. Users who install these updates do not need to use any workarounds.
To do this, open Settings, then Windows Update, go to Advanced options and select Optional updates. From there, install KB5089573 or later update. This will prevent the EFI partition install issue from occurring.
Microsoft recommends installing the latest update as it contains other fixes and improvements. The same resolution will be automatically released to all users via the June Patch Tuesday cumulative update.
Mitigation options if you do not install the KB5089573 optional update
Users who choose not to install the May 2026 optional update can use Known Issues Rollback (KIR), a Windows feature that undoes problematic updates delivered through Windows Update. KIR is automatically applied to consumer and unmanaged devices.
In an enterprise environment, administrators can resolve the issue manually by installing and configuring Group Policy provided by Microsoft. Known Issues Instructions for applying rollback group policies are available on Microsoft’s support website.
Preview cumulative update KB5089573 for Windows 11 versions 24H2 and 25H2 was released on May 26. It includes 30 changes, such as a low latency profile performance feature and various reliability improvements.
This update comes after several problems with Windows Update in 2026. Earlier this month, Microsoft confirmed that a security update released in April 2026 caused failures in third-party backup applications that relied on a vulnerable driver.
The company also fixed a Windows Autopatch bug that caused administrator-restricted driver updates to be deployed on some devices managed by Autopatch in the European Union.
