We have deployed an RDS Farm with 12 virtual RDS servers using Hyper V. Currently some users are not able to log on. After passing credentials to the connection broker, the session hangs on the "Welcome" screen.

Using resource monitor we've seen that svchost (with the "networkservice" service) has a CPU usage of 50%, when viewing the wait chain on the process it displays that it's waiting for a lsa.exe to finish.

We can't kill any of the users processes, even when trying with taskkill /f. Suspending lsa.exe did work but didn't have any effect. The networkservice also couldn't be restarted.

Also, if this happens, the current users logged on to the RDS server can't be displayed. Task manager crashes when viewing the users, RDS service manager crashes when viewing the users (even remotely) and the cmd command "query session" doesn't work.

No antivirus is installed on the RDS server. The only thing we can do is rebooting the server, which is not an option because of the fact that other users are in active sessions.

Does anyone have ANY idea what's going on? We didn't encounter this in our pre-production setup.