Microsoft has successfully addressed a significant issue that led to installation failures and the appearance of error code 0x800f0922 during the deployment of the May 2026 Windows 11 security update (KB5089549). This resolution comes after the company acknowledged the problem two weeks prior, attributing the failures to insufficient free space on the EFI System Partition (ESP). As a result, affected devices experienced automatic rollbacks of the update.
Users encountering these installation challenges were greeted with a message stating, “Something didn’t go as planned. Undoing changes.” Additionally, log entries such as “SpaceCheck” and “ServicingBootFiles failed” highlighted the underlying issue of inadequate ESP free space.
Details of the Issue
Microsoft clarified that the problem predominantly affects devices with limited free space on the EFI System Partition, particularly those with 10 MB or less available. While the installation might progress smoothly through initial phases, it typically falters during the reboot phase, reaching approximately 35–36% completion before failing.
On Friday, Microsoft announced that the issue has been resolved through the release of the Windows 11 KB5089573 preview cumulative update. This fix will be accessible to all users who install the upcoming June Patch Tuesday updates later this month.
The company stated, “This issue was resolved by Windows updates released May 26, 2026 (KB5089573), and later. We recommend you install the latest update for your device as it contains important improvements and issue resolutions, including this one.” Users installing updates released on or after May 26, 2026, will not need to implement a workaround for this issue. However, those using earlier updates and experiencing problems can utilize the following workaround.
For those who prefer not to install the May 2026 optional update, Microsoft offers a solution through the Known Issue Rollback feature. This Windows functionality allows users to reverse problematic updates that have been distributed via Windows Update.
In enterprise settings managed by IT departments, administrators can manually address this known issue by implementing and configuring the relevant Group Policy. Additional guidance on deploying Known Issue Rollback group policies is available on Microsoft’s support website.
On May 26, Microsoft released the KB5089573 preview cumulative update for Windows 11 versions 25H2 and 24H2, introducing 30 changes that enhance performance and reliability.
Earlier in the month, Microsoft also confirmed that the April 2026 security updates were causing failures in third-party backup applications that relied on a vulnerable driver. Furthermore, the company rectified a Windows Autopatch bug that led to the deployment of driver updates restricted by administrative policies on certain Autopatch-managed Windows devices across the European Union.
