Microsoft fixed an issue with the June 2026 Patch Tuesday: Windows updates installed via the Windows Update Standalone Installer (WUSA) from a network share had been failing for over a year. The fix is included in KB5079391 for Windows 11 and KB5094125 for Windows Server 2025.
Administrators rolling out updates via WUSA from a shared network folder had been encountering an annoying error since May 2025: ERROR_BAD_PATHNAME. The problem occurred when a network share contained multiple .msu files. Running a single .msu file locally worked fine, however.
Microsoft confirmed the bug in August 2025. The issue affected devices running Windows 11 24H2 and 25H2, as well as Windows Server 2025. In September 2025, Microsoft rolled out a Known Issue Rollback Group Policy as a temporary workaround for home users and unmanaged business devices. In enterprise environments that actively use WUSA and network shares, the problem has persisted to date.
Permanent fix via June 2026 updates
As part of the June 2026 Patch Tuesday, which also addresses more than 200 other vulnerabilities, Microsoft has now permanently resolved the WUSA issue for all affected systems. The fix is included in KB5079391 for Windows 11 and KB5094125 for Windows Server 2025.
Organizations that have not yet installed the latest update can work around the issue by first saving .msu files locally for installation. Microsoft also recommends waiting at least fifteen minutes after restarting Windows before checking the update history in Settings. After that short wait, the app will correctly display the installation status.
Devices that received the May 28, 2025 update (KB5058499) were susceptible to the error. After installing the June 2026 cumulative update, the workaround is no longer necessary.