Microsoft has confirmed that a long-standing Windows 11 update installation problem involving the Windows Update Standalone Installer (WUSA) has finally been fixed. The company says the resolution is included in updates released on March 24, 2026 and later, with KB5079391 specifically called out as the key update that addresses the issue in affected environments.
The problem primarily hit enterprise and IT-managed Windows 11 devices, not typical home PCs. In impacted setups, administrators attempting to install .msu update packages from a shared network folder could see the process fail with ERROR_BAD_PATHNAME. This was most likely to happen when the network share contained multiple .msu files in the same directory. Interestingly, the failure usually didn’t occur if the shared folder contained only a single .msu file, or if the update package was copied and installed locally from the device.
KB5079391 is listed as a preview update dated March 26, 2026 for Windows 11 version 24H2 and 25H2, and it corresponds to OS Builds 26100.8116 and 26200.8116. Microsoft also notes in its release health documentation that the issue was officially marked as resolved on March 26, even though the underlying fix began rolling out in updates released from March 24 onward.
According to Microsoft, the bug traces back to Windows 11 devices that installed updates starting May 28, 2025, beginning with KB5058499. In affected organizations, the error could appear whether someone double-clicked a .msu update file directly from a network share or ran WUSA against that same shared path.
Microsoft had previously taken steps to reduce the impact, including a Known Issue Rollback that began in September 2025 for most home users and non-managed business devices. For managed systems, IT administrators also had the option to apply a dedicated Group Policy as a mitigation. Now, with the March 2026 updates in place, Microsoft says systems running the March 24, 2026 update (or later) no longer need any workaround.
For organizations still on older builds, the practical workaround remains straightforward: copy the .msu files from the network share onto local storage first, then run the installation locally to avoid triggering the shared-folder path error.
Microsoft also mentions one more minor wrinkle administrators may notice after installing updates via WUSA: the Windows Settings app may temporarily continue to display a restart required message even after the update has successfully completed. In most cases, that status should clear automatically without additional action.
For IT teams that rely on WUSA for controlled deployments, the KB5079391 fix should significantly reduce failed update attempts and help restore a smoother, more predictable patching workflow—especially in environments where update packages are staged through shared network locations.
