Microsoft has recently addressed a significant issue affecting users of its Windows operating system, particularly those who encountered difficulties with the May 2026 update. The company has confirmed that the root cause of these problems has been identified, and a solution is being rolled out through an optional update, designated as KB5089573. By installing this update, users should find that their previous installation issues are resolved.
On May 12, 2026, Microsoft released the Patch Tuesday update (KB5089549) for various versions of Windows 11, including 25H2 and 24H2. This update introduced several notable enhancements, such as the new Xbox mode for desktop and various fixes related to explorer.exe. However, many users reported being unable to install the update, often encountering a perplexing error code, “0x800f0922.” This code typically indicates that the EFI System Partition (ESP) lacks sufficient free space.
Windows 11 mandates ESP, and it’s present on all PCs regardless of the OEM or Windows version you use
The EFI System Partition is a critical component of the Windows operating system, serving as the repository for boot files that the UEFI firmware relies on to initiate the operating system. This partition is automatically created during the Windows setup process and remains hidden in File Explorer due to its sensitive nature. Although it occupies only a small amount of space—typically around 256MB—it is essential for the proper functioning of the operating system.
Users can check the available storage on their ESP by executing the following command:
Get-Partition | Where-Object GptType -eq '{c12a7328-f81f-11d2-ba4b-00a0c93ec93b}' | Get-Volume | Format-List Size, SizeRemaining
When the ESP runs low on space, Windows updates may fail, a situation that became apparent with the May 2026 Update. Microsoft has since rolled back the problematic code via a server-side update. The company has provided further insights, explaining that while updates will download correctly, users may experience a stall at around 35–36% during the reboot process, leading to a rollback and the display of the message, “Something didn’t go as planned. Undoing changes.” This failure is logged with the error code 0x800f0922, and the Event Viewer will indicate insufficient free space on the ESP.
Why can ESP run out of storage and break Windows updates?
Typically, the ESP does not consume significant storage, maintaining a footprint of less than 100MB while retaining a majority of free space. However, certain circumstances, such as the installation of OEM updates like BIOS updates, can cause the partition to grow and potentially disrupt Windows Update installations. If the ESP has 10MB or less of available space, users may encounter installation failures.
While it is possible to manually increase the size of the ESP, this approach is not recommended unless one is well-versed in the process. Fortunately, Microsoft has developed a solution that alleviates the need for such adjustments. The company has stated that the May 2026 optional update (KB5089573 / Build 26200.8524 or newer) effectively addresses the underlying issues related to ESP space, ensuring that monthly updates can proceed without hindrance.
Microsoft encourages users who experienced issues with previous updates, including the May 2026 Patch Tuesday, to install the latest optional update. The company reassures users that all future updates will incorporate the fix for Windows Update failures. Therefore, those who prefer to wait for the next Patch Tuesday update, scheduled for June 9, 2026, can do so without missing out on the resolution.
