When you try to add a new user or object to AD, you may receive one of the following:
The object <name of user or object> could not be created.
The problem encountered was;
An attempt was made to add an object to the directory with a name that is already in use.
Windows cannot create the new user object because the name <UserName> is already in use. Select another name, and try again.
Windows cannot create the specified object because: The specified user already exists.
The user logon name you have chosen is already in use in this enterprise. Choose another logon name, and then try again.
In Windows 2000, the following three (3) things must be unique:
1. The downlevel logon name must be unique in the Windows 2000 domain, in order to support backwards compatibility with Windows NT 4.0.
2. The user logon name (User Principal Name, UPN) must be unique throughout the forest.
3. The Relative Distinguished Name (RDN), the "friendly" name, must be unique within the same container.
Printer, users, etc. can have the same name if they exist in different containers. <Jerold Schulman> can exit in the the Sales OU (Organization Unit) and in the Support OU.