Microsoft Confirms Windows 11 May Update KB5089549 Fails With Error 0x800f0922 on Dev

[harlan4096]

Microsoft has confirmed that the Windows 11 May 2026 Security Update KB5089549, released on May 12, is failing to install on some devices running versions 24H2 and 25H2. The installation often fails during the reboot process, usually around 35 percent, and displays error code 0x800f0922. In affected systems, the update rolls back and shows a message indicating that changes are being undone.

The main cause appears to be limited free space in the EFI System Partition. Devices with 10MB or less available space are most likely to experience this issue.

What Windows 11 KB5089549 Installation Failures Look Like

In addition to the rollback message, affected systems might display related entries in C:\Windows\Logs\CBS\CBS.log that point to insufficient free space on the EFI System Partition. Examples of these log entries include:

• SpaceCheck: Insufficient free space
  
• ServicingBootFiles failed. Error = 0x70
  
• SpaceCheck: used by third-party or OEM files outside of Microsoft's boot directories
  

These messages indicate that the issue is related to space rather than a broader problem with the installation process.

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