Hi Rainer Kling,
Greetings for the day!
You might experience Kerberos and New Technology LAN Manager (NTLM) authentication failures across devices that have duplicate Security IDs (SIDs).
These authentication failures can manifest as a variety of symptoms, including users are repeatedly prompted for credentials, shared network folders cannot be accessed via IP address or hostname, remote desktop connections cannot be established,.. etc
Please help provide a detailed description about the exact issue being faced by you (attach screenshots if possible) so that I could provide you the appropriate for temporary fix.
However, since this behavior is expected after the Windows Update, we strongly recommend applying the permanent solution by rebuilding devices with duplicate SIDs. This will ensure compatibility with the updates and help prevent further issues or side effectsAllow me to share the official article related with suggested resolution: https://learn.microsoft.com/troubleshoot/windows-server/setup-upgrade-and-drivers/windows-installations-disk-duplication
Additionally, please help note that the third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.
Would appreciate it if you find my response helpful and "Accept the Answer" 😊
Thanks and Regards!
Kate,