Why can't I create an organizational unit and child domain with the same name from one parent?

A. Although X.500 lets an organizational unit (OU) and child domain share a name, Active Directory (AD) doesn’t. Shared names in AD would cause problems with relative distinguished names (RDNs). If you try to create an OU and give it the same name as a child domain that already exists, you’ll get the error message

Active Directory

Windows cannot create the object because: An attempt was made to add an object to the directory with a name that was already in use.
Name-related properties on this object might now be out of sync.
Contact your network administrator.

If you try to create a child domain and give it the same name as an OU that already exists, you’ll get the error message

Active Directory Installation Failed

The operation failed because: The Directory Service failed to create the object CN=Sales, CN=Partitions, CN=Configuration, DC=Savilltech, DC=Com. Please check for possible system errors. "The directory service is busy"

Microsoft is aware of these restrictions, and no workarounds exist.