In older versions of Windows, you could set disconnected Remote Desktop Connections to timeout after a set period using the Remote Desktop Session Host Configuration.
In Windows Server 2012, you may find that Remote Desktop Session Host Configuration is missing from your Administration Tools – but don’t despair as you can configure this using group policy.
Open group policy admin and navigate to User Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services…
Expand Remote Desktop Session Host Configuration -> Session Time Limits and select “Set time limit for disconnected sessions”…
And finally, set the item to “Enabled” and select time limit that should elapse before ending the disconnected session…
