Microsoft fixes Windows update failures linked to WUSA installer

Microsoft fixed a bug causing Windows updates from May 2025 onward to fail with ERROR_BAD_PATHNAME when installed via WUSA from a network share. The fix arrived in June 2026 Patch Tuesday updates KB5079391 for Windows 11 and KB5094125 for Windows Server 2025. Affected enterprise devices can work around the issue by saving.msu files locally.