Microsoft Fixes Windows Update Failures Caused by WUSA Installer Bug

Microsoft has resolved a known issue that caused certain Windows updates to fail when installed using the Windows Update Standalone Installer (WUSA), as BleepingComputer reports. The problem mainly impacted enterprise environments and affected updates released from May 2025 onward.

Microsoft explained that the bug appeared when administrators tried to install MSU update packages from network shares containing multiple update files. In some cases, the installation failed with an ERROR_BAD_PATHNAME message, preventing the update from being installed successfully.

The issue affected devices running Windows 11 version 24H2, Windows 11 version 25H2, and Windows Server 2025. According to Microsoft, home users were unlikely to encounter the problem because WUSA is rarely used on consumer PCs.

Microsoft first confirmed the issue in August 2025 after organizations reported update deployment failures. The bug impacted systems that installed updates released on May 28, 2025, starting with KB5058499 and subsequent updates.

Microsoft Rolls Out Permanent Fix

Microsoft initially mitigated the issue for home users and unmanaged business devices through a Known Issue Rollback. The rollback began rolling out in September 2025 and automatically disabled the problematic code on affected systems.

The company has now released a permanent fix as part of the June 2026 Patch Tuesday updates.

The correction is included in KB5079391 for Windows 11 and KB5094125 for Windows Server 2025.

Organizations that have installed the latest cumulative updates should no longer experience failures when deploying updates through WUSA from network locations.

Temporary Workaround Remains Available

For systems still running older affected updates, Microsoft recommends copying MSU update files to local storage before starting the installation process.

The company also recommends waiting at least 15 minutes after restarting Windows before reviewing Update History. This allows the Settings app enough time to accurately reflect whether a WUSA-installed update completed successfully.

More Windows Update Fixes Arrive in June 2026

The WUSA-related fix is one of several Windows update issues Microsoft addressed this month.

The company recently added the June 2026 Patch Tuesday updates to the Windows 11 Media Creation Tool, enabling new installations to include the latest security updates from the start.

Microsoft also fixed a Windows Server 2025 issue that could trigger BitLocker recovery after installing updates. Additionally, the June 2026 Patch Tuesday release patched more than 200 security vulnerabilities across Windows.

Microsoft has further warned that some PCs upgraded to Windows 11 24H2 or Windows 11 25H2 may still encounter problems installing future monthly updates, and the company is continuing to investigate those reports.