By default, after a few seconds, the last session you were using is automatically re-loaded and started.
You can can modify this behavior, either by designating a specific session to auto-launch irrespective of the most recent manual selection, or by disabling the feature entirely.
Important: Modifying this feature requires changes to the Registry. We strongly recommend that edits to the registry be performed only by experienced persons, as the system can be rendered inoperable if this is done improperly.
To change default startup behavior
Locate HKEY_LOCAL_MACHINE\SOFTWARE\VIZRT\XD\ADMIN SCREEN
Add a new key: auto_launch_session
Set the value for this key to the name of an existing session.
This session will then automatically opens on launch (instead of the last open session).
If the specified session does not exist, the auto-launch feature is disabled..
Similarly, by setting auto_launch_session to _Disabled (or some other suitable string) rather than a real session name you can effectively disable auto-launch.