In early July 2025, system administrators worldwide encountered significant synchronization issues with Windows Server Update Services (WSUS). This disruption, which began shortly after Microsoft released its monthly security updates, led to widespread reports of WSUS servers failing to sync with Microsoft's update servers.
Administrators reported error messages such as "A connection attempt failed" and "The operation has timed out," indicating that WSUS servers were unable to establish connections with Microsoft's update servers. These issues were first noted on July 9, 2025, with reports emerging from various organizations experiencing synchronization failures. The problem was not isolated, as multiple administrators from different companies confirmed similar experiences. For instance, a German blog highlighted that WSUS synchronization problems were observed as early as 2:00 a.m. on July 9, 2025. (borncity.com)
Microsoft initially did not publicly acknowledge the issue. However, administrators who contacted Microsoft Support received responses indicating that the company was aware of the problem and actively investigating it. The issue was attributed to defective metadata associated with .NET Framework 3.5 updates released in July 2025. This faulty metadata caused WSUS servers to initiate full synchronizations, placing excessive load on the servers and leading to unresponsiveness and timeout errors. To mitigate the issue, Microsoft advised administrators to temporarily uncheck the "Updates" classification in WSUS settings, effectively bypassing the problematic updates. (borncity.com)
Shortly thereafter, Microsoft confirmed that the issue had been resolved by expiring the update that caused the problem. This action restored normal synchronization functionality for WSUS servers. The incident underscores the critical importance of robust testing and quality assurance processes in the deployment of updates, as well as the need for clear and timely communication from software vendors during widespread technical issues.
This event also highlights the challenges associated with managing large-scale update infrastructures and the potential impact of metadata errors on system performance. Administrators are reminded of the importance of monitoring update deployments closely and having contingency plans in place to address unexpected issues promptly.
Source: gHacks Technology News Microsoft caused and fixed a WSUS Synchronization issue that affected systems worldwide - gHacks Tech News
