The server %SERVERNAME% has detected duplicate GUIDs in the directory services. The duplicate existing machine names are:
%SUBERROR%

Having duplicate GUID in the directory service can cause unexpected results because the server might get the machine names in a random order causing the machine to have a different name every time you reinstall it.

Press enter to create the machine %MACHINENAME% anyway and clean up the existing machine account(s) later. If you entered the wrong name, press ESC to cancel and go back to the Main Menu.