WSUS synchronisation issue

ok it's strange but finally it works after maybe more than 1 hour...

Hello matteu31, thank you for posting in the Microsoft Q&A community.

The error SqlException occurred. Number 50000 and message invalid update identity (AtLeastOne Prerequisite) in XML for update means that WSUS is attempting to parse update metadata (XML) downloaded from Microsoft Update and insert it into the local SUSDB database, but the SQL stored procedure is rejecting it due to a malformed prerequisite schema.

Because you have replicated this exact failure across clean installations of Windows Server 2019, 2022, and 2025, this indicates a transient server-side issue on Microsoft's end. A recently published update on the Microsoft Update catalog likely contains malformed XML metadata. When your new WSUS server attempts its initial catalog sync to discover available products, it pulls this broken metadata, causing the local database transaction to fail and halting the wizard.

Since the GUI Configuration Wizard can get permanently stuck when encountering a catalog exception, bypassing the wizard and forcing the synchronization through PowerShell can handle the exception more gracefully or skip the problematic metadata block.

1. Click Cancel to close the WSUS Configuration Wizard.
2. Open an elevated PowerShell prompt and run the following commands to initiate a sync manually:

$wsus = Get-WsusServer
$wsus.GetSubscription().StartSynchronization()

3. Open the WSUS Administration Console and navigate to the Synchronizations node to monitor the progress. If it succeeds, you can then manually navigate to Options > Products and Classifications to configure your server.