Microsoft fixes WUSA update-install failures on Windows 11 and Server 2025
Summary
Microsoft fixed WUSA failures affecting Windows 11 24H2/25H2 and Windows Server 2025 when installing updates from network shares containing multiple .msu files. June 2026 cumulative updates include the fix.
Key points
- WUSA installations could fail with ERROR_BAD_PATHNAME when updates were run from network shares containing multiple .msu files.
- The issue affected Windows 11 24H2/25H2 and Windows Server 2025, including updates released from May 28, 2025 onward.
- Microsoft says the issue did not occur with a single .msu file or when update files were stored locally.
- A Known Issue Rollback partially mitigated the problem for home and non-managed business devices beginning in September 2025.
- Microsoft included the fix in June 2026 cumulative updates KB5079391 for Windows 11 and KB5094125 for Windows Server 2025.
- For systems using earlier updates, Microsoft advised saving .msu files locally before installing them.
Article Details
- Event Type
- Windows update installation issue resolved by Microsoft
- Impact
- WUSA installations of Windows updates from network shares containing multiple .msu files could fail with ERROR_BAD_PATHNAME. The issue affected Windows 11 24H2/25H2 and Windows Server 2025 devices, particularly on enterprise networks. Microsoft resolved it in June 2026 cumulative updates; saving .msu files locally was a workaround.
Vendors
Products
Windows 11The problem affected Windows 11 24H2/25H2 and Windows Server 2025, and is now resolved in June 2026 cumulative updates for KB5079391 and KB5094125.Windows Server 2025The problem affected Windows 11 24H2/25H2 and Windows Server 2025, and is now resolved in June 2026 cumulative updates for KB5079391 and KB5094125.Windows Update Standalone Installer (WUSA)Microsoft has fixed a known issue that caused Windows updates released since May 2025 to fail when installed via the Windows Update Standalone Installer (WUSA) from a network share.