kb5089549 error

The kb5089549 error is a Windows 11 cumulative update failure that produces error code 0x800f0922. This error occurs on version 24H2 and 25H2 PCs when the EFI System Partition has approximately 10 MB or less free space, causing the update to roll back. Microsoft has issued a Known Issue Rollback for consumer and unmanaged business devices, often resolved with a restart. For managed fleets, administrators are directed to Group Policy-based mitigation. The error highlights how Windows Update can turn a hidden implementation detail into a patching blocker.