Microsoft has acknowledged that the recent May 2026 Security Update for Windows 11 is encountering installation issues on certain devices, manifesting as error code 0x800f0922. This complication primarily affects systems operating on versions 24H2 and 25H2 following the installation of update (KB5089549), which was released on May 12. The failures typically arise during the reboot phase of the installation process, often around the 35 percent mark.
The root of the problem lies in devices that have limited free space within the EFI System Partition (ESP). Specifically, systems with 10MB or less available space are at a higher risk of experiencing installation failures. When the update process encounters a snag, the operating system reverts the changes and presents the familiar recovery message: “Something didn’t go as planned. Undoing changes.”
For consumer and unmanaged business devices, Microsoft has implemented a Known Issue Rollback (KIR). In many instances, simply restarting the computer and checking for updates again may rectify the issue. However, for devices managed by organizations, network administrators are required to manually deploy a Group Policy workaround. Microsoft is also providing a direct fix for systems that continue to experience installation failures.
How to fix error 0x800f0922 on Windows 11
Disclaimer: Editing the Registry can be risky and may lead to irreversible damage to your installation if not done correctly. It is advisable to create a full backup of your PC before proceeding.
To address the issue, Microsoft suggests modifying a Registry value to decrease the reserved padding that Windows 11 utilizes within the EFI partition during servicing. Follow these steps:
- Open Start.
- Search for Command Prompt, right-click the top result, and select “Run as administrator”.
- Input the following command and press Enter: reg add “HKLMSYSTEMCurrentControlSetControlBfsvc” /v EspPaddingPercent /t REG_DWORD /d 0 /f
After executing the command, continue with the following steps:
- Restart the computer.
- Open Settings.
- Click on Windows Update.
- Press the Check for updates button.
Upon completing these steps, the update KB5089549 should download and install smoothly on Windows 11. Microsoft has indicated that a permanent solution is in the works and will be included in a future Windows update.
Windows Central’s Take
It’s likely that many users will remain unaware of this issue, as Microsoft has already initiated a fix through the Known Issue Rollback. In numerous cases, a simple restart and subsequent check for updates may suffice to install the update successfully. However, this situation can be perplexing for users, as the computer may display ample free storage space, yet the update may still fail due to a concealed system partition operating in the background.
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