Microsoft confirms Windows 11 security update install issues

Source: Bleeping Computer

Issue Overview

Microsoft has confirmed that the May 2026 Windows 11 security update KB5089549 fails to install on some systems, resulting in 0x800f0922 errors.
The problem is caused by insufficient free space on the EFI System Partition (ESP), which forces the update to roll back automatically.

“This issue affects devices with limited free space on the EFI System Partition (ESP), especially when the device has 10 MB or less space available.” – Microsoft

“On affected devices, the installation might proceed through the initial phases but fail during the reboot phase at approximately 35–36 % completion.”

Symptoms & Log Entries

• Error code 0x800f0922 during installation.

• Message: “Something didn’t go as planned. Undoing changes.” after the rollback.

• Log entries indicating ESP space issues, for example:

  SpaceCheck: Insufficient free space
  ServicingBootFiles failed. Error = 0x70
  SpaceCheck:  used by third‑party/OEM files outside of Microsoft boot directories

Mitigation

Known Issue Rollback

Microsoft recommends using the Known Issue Rollback feature, which reverses buggy updates delivered via Windows Update.

• Guidance: Known Issue Rollback – Microsoft Tech Community

Group Policy (Enterprise)

In managed environments, administrators can deploy a Group Policy to temporarily disable the problematic change:

1. Download the appropriate MSI for your Windows version:
   Group Policy MSI (KB5089549)

2. Install and configure the policy for your version of Windows.

3. Restart the device(s) to apply the setting.

“You will need to install and configure the Group Policy for your version of Windows to resolve this issue,” Microsoft notes. “The Group Policy will temporarily disable the change causing this issue.”

• Detailed deployment instructions: Deploy Known Issue Rollback via Group Policy

Additional Context

• KB5089549 was released alongside dozens of other bug fixes, security patches, and improvements, including a fix for a separate issue that caused some Windows 11 systems to boot into BitLocker recovery after the April 2026 security updates.

  • Source: BleepingComputer – Windows 11 KB5089549 and KB5087420 cumulative updates released

• Earlier in April 2026, Microsoft addressed:

  • A Windows Autopatch bug that deployed driver updates restricted by administrative policies on some EU devices.
    • Source: BleepingComputer – Microsoft fixes Windows Autopatch bug
  • Failures in third‑party backup applications caused by a vulnerable driver.
    • Source: BleepingComputer – Backup failures caused by vulnerable driver