RDP supports only one shadow session per client


The Microsoft Terminal Server \ Remote Desktop Server implementation supports only one shadow session per client.

More Information

This is by design.

More information about connecting to a shadow session can be found in the following Knowledge Base articles:

278845 How to Connect to and Shadow the Console Session with Windows Server 2003 Terminal Services

320191 HOW TO: Use the SHADOW Command to Remotely Monitor an Active Session of Another User in Windows 2000 Terminal Services