Windows Server: WSUS install and 1st sync fails

[German]I'm posting just a warning for Windows Server administrators using WSUS here on the blog for informational purposes, as it was recently brought to my attention by two readers. WSUS currently cannot be reinstalled on Windows Server and/or fails during the initial synchronization. This is something administrators may encounter if they want to set up a new system with WSUS.

Two reader reports about this WSUS issue

German blog reader Marc K. contacted me by email late in the afternoon on July 2, 2026 (thanks for that) and wrote that he was "currently in a Windows Server course and was supposed to install WSUS as a role." However, he said this wasn't possible because the database wouldn't allow it. The XML data doesn't seem to match. Marc sent me the following error logs by email.

2026-07-02 13:35:30.230 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update 023FBB11-14F5-4188-9C99-3CF16AA09A79\100
2026-07-02 13:35:30.241 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update 872C37AF-7303-452E-A79D-9996339EBAC7\100
2026-07-02 13:35:30.261 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update EA293276-0BCD-42B0-AC26-803F002E4AAF\100
2026-07-02 13:35:30.273 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update D953C4E3-4A17-4BE5-A62A-194A48FBE726\100
2026-07-02 13:35:30.288 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update 3CB61571-0F24-460A-88A4-D8BA91086CEE\100
2026-07-02 13:35:30.292 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update F79191BF-5F81-4B85-92E0-BBBDE6FC9479\100
2026-07-02 13:35:30.304 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update F8B4C8BE-B1C0-4FCB-AE66-1AD17C467089\100
2026-07-02 13:35:30.352 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update AB2221A6-5C0A-499B-ABE2-FDF428AC4DC2\100
2026-07-02 13:35:30.368 UTC  Warning  WsusService.21  DBConnection.ExecuteCommandNoResult  SqlException occurred. Number 50000 and message invalid update identity in XML for update B8468628-4D28-4A00-98E0-C32556E15332\100

It seems that the issue has happened since June 15, 2026, and is mentioned at several Microsoft Q&A posts.

 Some reports at Microsoft Q&A

Marc pointed me to the following sources on Microsoft Q&A where the issue has already been discussed:

• WSUS initial configuration fails with SqlException 50000 invalid update identity
• Windows Server 2025 Standard – WSUS – Synchronisation failing
• Downloads to WSUS not working in my MECM system with Software Update Point

In the forum posts above, this applies to Windows Server 2022 Standard and Windows Server 2025.

A note from my Microsoft source

Just three hours earlier, I received a personal message from a Microsoft source (thanks for the info), stating that there are "currently issues with the initial sync of newly installed WSUS servers." It also referred to the first Microsoft Q&A forum post in the list above.

It was noted that very little information is available so far because the problem only occurs during the first sync, and not many new WSUS servers are being set up these days. But anyone who has to perform this task will run into the problem.

The information from my Microsoft source was that "if the affected administrator opens a support ticket at Microsoft, they will receive a workaround that involves manually importing the catalog via a script." My source is currently trying to clarify internally at Microsoft whether and when a fix from Microsoft will be available. He suspects that no hotfixes will be necessary on the customer side.