You may never need this, but if you do, it is the best trick ever. I administer my XSERVER remotely via the built in Apple VNC. However, the VNC service occasionally crashes, and locks my session. It also refuses any more VNC logins. This is particularly frustrating when I am off site! Apple has analyzed this and has no explanation or fix. BUT!! One talented and determined technician came up with this magic workaround. If SSH access is enabled on the server, you can connect to the server via an SSH client (PUTTY is great for Windows clients), and run this command: sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/kickstart -restart -agent You must log in with admin rights, and must enter the admin password again to run the command. It can take a minute to run. After it finishes, VOILA! you can login again via VNC. Believe me, this is a Godsend if you need it!