Microsoft fixes Windows 11 KB5089549 installation failures caused by low EFI space
Summary
Microsoft says KB5089573 and later updates fix KB5089549 installation failures on Windows 11 devices with low EFI System Partition space. Known Issue Rollback and Group Policy are workarounds for devices not yet updated.
Key points
- KB5089549 could fail with error 0x800f0922 when devices had insufficient free space on the EFI System Partition, especially 10 MB or less.
- Affected installations could roll back during reboot at about 35–36% completion.
- Microsoft says the issue was resolved in the May 26, 2026 KB5089573 update and later releases.
- Users who have not installed the fix can use Known Issue Rollback; enterprise administrators can apply a Group Policy workaround.
Article Details
- Event Type
- Microsoft resolved a Windows 11 security update installation issue in KB5089573 and later updates.
- Impact
- Devices with limited free space on the EFI System Partition could fail to install KB5089549 with error 0x800f0922 and roll back during reboot at approximately 35–36% completion. Microsoft says the issue is resolved in updates released May 26, 2026, and later; Known Issue Rollback and a Group Policy workaround are available for affected devices that have not installed a fixing update.