If the agent is already active this call has no effect. When starting, the agent will raise an Initializing event which can be canceled. If it cancels then the session has not been started. All calls to the agent are safe whether it has been activated or not.
Requirements
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2