Microsoft has identified synchronization delays and timeout errors affecting Windows Server Update Services (WSUS), which risks the timely delivery of Windows updates. WSUS is a management tool for distributing Windows updates across networks. Microsoft deprecated WSUS in September 2024 but continues to provide security fixes and updates. The synchronization issue has led to failures and delays in downloading update metadata, particularly impacting Windows 11 version 23H2 and later, Windows 10 version 1607, and Windows Server 2012 and later. This issue began around July 13, 2026, with mitigation efforts starting on July 18, 2026. Microsoft has released a partial fix for newly installed or rebuilt WSUS servers, while existing servers may still face challenges. The company is developing additional fixes and guidance. In previous years, Microsoft dealt with other WSUS-related issues affecting enterprise clients.