Microsoft Fixes Windows 11 KB5089549 Install Failures Caused by Limited EFI Partition

[harlan4096]

Microsoft has fixed the known issue that caused installation failures and 0x800f0922 errors when deploying the May 26, 2026, Windows 11 security update KB5089549.

The solution is included in the KB5089573 preview cumulative update released on May 26 and will be available to all users through the June Patch Tuesday updates later this month.

The failures were due to insufficient free space on the EFI System Partition (ESP), which led the update to roll back automatically on affected devices.

What Was Causing KB5089549 Install Failures and How to Fix Them

Microsoft confirmed two weeks ago that the problem affected devices with limited free space on the EFI System Partition, especially those with 10MB or less available. On these systems, the installation process would begin normally but fail during the reboot phase at around 35 to 36 percent completion.

Affected users saw a message stating, "Something didn't go as planned. Undoing changes," when the update rolled back. Logs from impacted systems included entries like "SpaceCheck" and "ServicingBootFiles failed," which pointed to insufficient free space on the EFI System Partition.

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