Microsoft shares manual fix for WSUS sync delays and timeouts
Microsoft has shared a manual fix to help IT administrators fix Windows Server Update Services (WSUS) servers affected by a known issue that causes Windows Update scans to fail or time out.
Intelligence analysis by Llama
Microsoft has shared a manual fix to help IT administrators fix WSUS servers affected by a known issue that causes Windows Update scans to fail or time out. The fix involves cleaning up unneeded metadata and updating the MaxXMLPerRequest value to its default setting.
Imagine you have a big library of books, and every time you want to find a new book, you have to search through the entire library. This is similar to what's happening with WSUS servers, where the search process is taking too long because of too much extra information. Microsoft has given IT administrators a way to clean up this extra information so that the search process can work faster.
Analysis
A Known Issue Affects WSUS Servers
Microsoft has shared a manual fix to help IT administrators fix Windows Server Update Services (WSUS) servers affected by a known issue that causes Windows Update scans to fail or time out. This issue affects both client (Windows 10, version 1607 and later) and server (Windows Server 2012 and later) platforms.
The issue causes increased synchronization times or sync operation timeouts due to a buildup of publishing metadata. Microsoft rolled out a service-side mitigation on Saturday to address the issue for newly installed or rebuilt WSUS servers. However, organizations with existing WSUS server installations that are experiencing long sync times can benefit from manual steps to clean up unneeded metadata.
Cleaning Up Unneeded Metadata
To clean up unneeded metadata, admins need to back up each SUSDB database, run a cleanup query from SQL Management Studio against all SUSDB databases (including WSUS replicas), and update the MaxXMLPerRequest value to its default setting. After the cleanup process, the first Windows Update scan may take longer than usual, but subsequent scans will return to normal timing.
Additional Steps
After the cleanup, admins need to reindex SUSDB, run the WSUS Server Cleanup Wizard, and then run IISReset or recycle the WsusPool application pool to clear cached catalog state. The client-side DataStore.edb does not shrink automatically after the detectoids are removed, but this is expected and does not affect scan performance.
Previous Issues
Microsoft has addressed similar WSUS issues that prevented admins from deploying the latest Windows updates in May 2025, July 2025, and August 2025.
Key points
- Microsoft has shared a manual fix to help IT administrators fix WSUS servers affected by a known issue that causes Windows Update scans to fail or time out.
- The fix involves cleaning up unneeded metadata and updating the MaxXMLPerRequest value to its default setting.
- Admins need to back up each SUSDB database, run a cleanup query from SQL Management Studio, and update the MaxXMLPerRequest value to its default setting.
- After the cleanup process, the first Windows Update scan may take longer than usual, but subsequent scans will return to normal timing.
With the manual fix, IT administrators can quickly resolve the issue and get their WSUS servers back to normal functionality. This will help ensure that Windows updates are deployed smoothly and that users have access to the latest security patches.
If the manual fix is not applied correctly, it could lead to further issues with WSUS servers, including increased synchronization times or sync operation timeouts. This could cause delays in deploying Windows updates, which could leave users vulnerable to security risks.
