Apple Remote Desktop 3: Clients become unavailable if screen locked or curtained during login
Symptoms
If you are using Remote Desktop to control a client running Mac OS X 10.5 in Curtain mode, or you Lock the Screen of the client before taking Control, then you log in as a user on the remote client, the control session will end and you will not be able to take control of the computer again until it is restarted.
Products Affected
Apple Remote Desktop 3.X
Resolution
Do not use Lock Screen or Curtain mode on a Remote Desktop client if the client computer is at the login window. If necessary, use Curtain mode to enter the username and password in the login window, then end the Curtain mode session and start a normal (not Curtain mode) session to click the Login button.
After the login process is finished, and the desktop and menu bar appear on the remote client, you may start a new Curtain mode session.
This document will be updated as more information becomes available.