After rebooting a Windows Server the preconnect screen will not been displayed also after a successful RDP login.
It always requires the service to be restarted after the first RDP login.
Here is the example procedure:
1) Start Windows Server, UVNC service running with rdpmode=1
2) Try to connect with UVNC Viewer - No preconnect screen, console session appears directly, it seems working as designed. (==> Only console is active, no RDP sessions available)
3) Close UVNC Viewer
4) Connect via RDP to the Windows Server (An RDP session is now active)
5) Try to connect with UVNC Viewer - No preconnect screen, console session appears directly, seems not working as designed ! (One RDP session is active, preconnect screen should appear)
6) Close UVNC Viewer
7) Restart the UVNC Server service

As soon as there are all RDP sessions closed, the service must be restarted again.
It seems it is a bug in the winvnc server software.
Could anybody fix this behavior? Or could you provide an workaround?
Thanks!