Active Directory Domain Services could not remove the application directory partition %1 because this partition has one or ...

Active Directory Domain Services could not remove the application directory partition %1 because this partition has one or more child partitions or cross-refs.  Remove the child partition or cross-refs first and retry.  Dsmgmt.exe can be used to remove partition metadata.
 Skipping this step will result in an irreparable directory partition hierarchy for this forest.