When remote controlling a computer running the DAgent, if the computer is locked during remote control session or if someone logs off during remote control session, the session dies without any disconnect message.
If no one is logged in to the remote computer running Dagent, the remote session won’t connect
The DagentUI is the client-side component that executes the Deployment Server remote control functions.
The DagentUI executes within the security context of the locally logged in user. So if the desktop is locked then DagentUI cannot capture the screen or send the input because the user does not have rights. In the case of Windows Vista and Windows Server 2008 when the UAC feature is enabled then the remote control functionality is blocked the moment UAC prompt appears. This occurs because the DagentUI cannot capture the screen or send the input from the alternate user session that is activated when the UAC prompt is displayed.
The DAgent and DAgentUI components are designed not to execute any jobs or tasks as the local system account when the client machine has an active logged on user session to prevent opening security vulnerabilities.
Here is the information on remote control with Dagent:
When UAC is enabled and a UAC consent dialog appears it will block the any remote control activity.
Deployment Solution 6.9 SP1, 6.9 SP2, 6.9 SP3
Windows* Vista* with UAC enabled
Windows Server 2008* with UAC enabled
Windows 7 with UAC enabled