"Windows updates installed using the Windows Update Standalone Installer (WUSA) might fail with error ERROR_BAD_PATHNAME, when the update is installed using WUSA or double-clicking a .msu file from a network share that contains multiple .msu files," Microsoft said when it acknowledged the issue in August 2025.
How Microsoft described the failure and its scope
Microsoft traced the problem to the Windows Update Standalone Installer (WUSA), a built-in Windows command‑line tool that installs and uninstalls Microsoft Standalone Update (.msu) files through the Windows Update Agent API. The company reported the error manifests as ERROR_BAD_PATHNAME when administrators attempt to run WUSA or double‑click a .msu file located on a network share that contains multiple .msu files.
According to Microsoft, the bug was linked to updates released May 28, 2025 (KB5058499) and later. It primarily affected enterprise networks because WUSA is not a common installation method on home devices; Microsoft said the bug does not occur when installing a single .msu file from a network share or when the files are stored locally.
Which product versions were affected
Microsoft identified the issue on Windows 11 24H2/25H2 and Windows Server 2025 devices. The company specifically tied the failures to enterprise deployments where administrators rely on WUSA against network shares rather than local storage.
Mitigations before the June 2026 update
Microsoft first issued an automatic mitigation for home and non‑managed business devices using a Known Issue Rollback Group Policy beginning September 2025. For administrators still encountering the problem on affected systems, Microsoft advised a practical workaround: save the .msu files locally on the device and install from that location.
Microsoft also recommended a timing adjustment after installing an .msu file via WUSA: "If you've restarted Windows after installing an .msu file via WUSA, please wait 15 minutes or more before checking the Update History page in Settings. After this short delay, the Settings app should properly indicate if the update installed successfully," the Windows release health dashboard update said.
Fix delivered as part of June 2026 Patch Tuesday
The long‑running failure was addressed in the June 2026 cumulative updates. Microsoft released fixes in Windows 11 (KB5079391) and Windows Server 2025 (KB5094125) as part of that Patch Tuesday, resolving the WUSA behavior for all affected systems.
Related update-delivery problems earlier in 2025
Microsoft previously resolved a separate April 2025 issue that prevented enterprise customers from installing the April 2025 security updates via Windows Server Update Services (WSUS). The company also noted an identical bug that caused the August 2025 Windows 11 updates to fail with 0x80240069 errors.
In addition, Microsoft warned earlier this week that customers may experience issues installing the latest monthly updates on some Windows devices upgraded to Windows 11 24H2 or 25H2.
What this means for enterprise admins and home users
- Enterprise administrators: If you relied on WUSA against network shares to deploy multiple .msu files, confirm systems have received KB5079391 or KB5094125 from the June 2026 cumulative updates; until those patches were applied, Microsoft recommended copying .msu files locally before installation.
- Home and non-managed business users: Microsoft mitigated the issue automatically for these device classes beginning September 2025 via a Known Issue Rollback Group Policy, reducing the need for manual intervention on most consumer machines.
- IT operations and change teams: After installing .msu files via WUSA and rebooting, allow at least 15 minutes before checking Update History so the Settings app can reflect installation status correctly, per Microsoft's release health guidance.
The failure tied to WUSA underscoreed how a single installer pathway — in this case, installing multiple .msu files from a network share — can ripple through enterprise update processes. Microsoft’s June 2026 cumulative updates close that window for affected Windows 11 24H2/25H2 and Windows Server 2025 systems; administrators who used the local‑copy workaround or who delayed checking Update History should now verify that KB5079391 or KB5094125 is applied to see the issue fully resolved.
