Microsoft's Windows Server Update Services (WSUS) has suffered "severe degradation," causing painfully slow synchronisations or outright timeouts for organisations trying to fetch updates. The cause is a build-up of publishing metadata rather than any recent Patch Tuesday release, but it matters because WSUS remains widely used by enterprises to deploy and manage updates, and slow syncing can delay patch testing and deployment, leaving systems exposed for longer.

Microsoft says the problem intensified from 13 July 2026, and on 18 July it deployed a fix that restores normal synchronisation for newly installed or rebuilt WSUS servers, but existing affected deployments remain stuck, with Microsoft still working on mitigation steps to safely strip out the problematic metadata. The issue affects nearly every desktop and server platform still supported by WSUS, from Windows 11 26H1 back to Windows 10 1607 and Windows Server 2012. Although Microsoft deprecated WSUS in October 2024 in favour of cloud-based alternatives, many administrators kept using it as a supported production tool, and for now there is little they can do but wait for further guidance.