"Synchronization times and sync operations on WSUS servers have been restored and are operating normally for new WSUS installations and rebuilds," Microsoft said.
What Microsoft reported and the short timeline
Microsoft disclosed a known Windows Server Update Services (WSUS) issue that causes Windows Update scans to fail or time out and shared both a service-side mitigation and a manual remediation. According to the company, heightened impact from the problem was first observed beginning on July 13. In response, Microsoft rolled out a service-side mitigation on Saturday to address the problem for newly installed or rebuilt WSUS servers. On Monday Microsoft published manual steps for administrators who still experience long synchronization times or synchronization operation timeouts.
Which systems are affected and how operations are disrupted
The known WSUS sync issue affects both client and server platforms identified by Microsoft: client systems running Windows 10, version 1607 and later, and server platforms running Windows Server 2012 and later. On impacted WSUS servers, administrators are unable to deploy the latest Windows updates via WSUS or Configuration Manager because synchronization times increase and sync operations can time out. Microsoft attributes the slowdown and timeouts to a buildup of publishing metadata in existing WSUS installations.
The manual fix: three core steps administrators must take
For organizations with existing WSUS installations still experiencing long sync times, Microsoft provided a manual cleanup path. The company said the cleanup requires administrators to:
- Back up each SUSDB database.
- Run a cleanup query from SQL Management Studio against all SUSDB databases, including WSUS replicas, to remove unneeded publishing metadata.
- Update the MaxXMLPerRequest value back to its default setting.
Microsoft emphasized that the metadata targeted by this process "is present in existing WSUS installations but can be safely removed."
Steps to follow after the database cleanup and expected behavior
Microsoft advised additional actions after the cleanup query completes. Administrators should reindex SUSDB, run the WSUS Server Cleanup Wizard, and then either run IISReset or recycle the WsusPool application pool to clear cached catalog state. Microsoft cautioned that the first Windows Update scan after the cleanup may take longer than usual, but subsequent scans should return to normal timing.
One notable operational detail: the client-side DataStore.edb file does not shrink automatically after the detectoids are removed. Microsoft described this as expected and said it "does not affect scan performance."
What this means for technologists, affected enterprises, and end users
- Technologists and security teams: Teams responsible for WSUS infrastructure must plan a maintenance window to back up SUSDB databases and run the SQL cleanup and post-cleanup tasks. They will also need to monitor initial post-cleanup scans, which Microsoft warns may run slower before returning to normal.
- Affected enterprises and procurement leaders: Organizations using WSUS or Configuration Manager should verify whether their installations are new or rebuilt—those benefited from the service-side mitigation Microsoft deployed on Saturday—but prepare to apply the manual cleanup if their existing servers still show long sync times or timeouts.
- End users and IT support desks: Users may see delayed update scans during the immediate post-cleanup period. Microsoft noted that persistence of the DataStore.edb file size is expected and should not be interpreted as a lingering performance problem.
Microsoft has confronted similar WSUS issues in the recent past; the company addressed related synchronization problems in May 2025, July 2025, and August 2025. For administrators who continue to observe synchronization problems after following the published manual steps, Microsoft’s dashboard and guidance are the current reference points for next steps.
Source: BleepingComputer — Microsoft shares manual fix for WSUS sync delays and timeouts
