Has anyone else experienced Remote Desktop Connection problems after installing the September security updates on Windows Server 2019? The connection sometimes works, but after disconnecting, later attempts can hang indefinitely at "Securing network connection" or fail to connect entirely. I've also noticed possible issues with locally hosted SQL Server services on a non-FCI setup. What is the recommended remediation?
3 Answers
The out-of-band update released around September 14 is intended to correct the RDP problem. In this case, the symptom is not just a timeout—it can be an intermittent failure where one connection succeeds, but the next attempt remains stuck at “Securing network connection.” Apply the correct update for the operating system build and restart the server.
Yes, this was a known issue with the September updates. Microsoft released an out-of-band fix, so install the package that matches your specific Windows or Windows Server version. The affected KBs mentioned were KB5129195, KB5129236, KB5129238, and KB5129239. Use the Microsoft Update Catalog or your normal patch-management process, then reboot the server and test RDP again.
Several administrators reported having to restart or otherwise recover terminal servers after RDP stopped accepting connections. If remote access is currently unavailable, use an alternate management path such as the hypervisor console, out-of-band management, or another administrative channel to install the fix and reboot.

Thanks. I’m also seeing some instability with SQL Server services hosted locally on the same Windows Server 2019 machine, so I’ll check whether the out-of-band update addresses that as well.