Microsoft has addressed a bug that blocked Windows updates from installing when deployed through the Windows Update Standalone Installer (WUSA) from a network share. The issue affected updates released since May 2025, causing them to fail silently or with error messages.
The flaw impacted enterprise environments that rely on WUSA for offline or network-based patching. Microsoft released a fix via a Windows Update servicing stack update, which must be applied to enable affected machines to accept future patches through the installer.
Technically, the problem arose when WUSA attempted to initialize installations from remote paths, triggering a file-access error. The servicing stack update corrects the handling of network paths in the installer's engine.
Microsoft advises administrators to install the latest servicing stack update manually in environments where automatic updates are not configured. No further workarounds are required after applying the patch.
The company did not disclose whether the bug was reported externally or discovered internally. Enterprises using Configuration Manager or WSUS may encounter the issue until the servicing stack update is distributed through those channels.