Based on your requirement, you can enable Item reconciliation to avoid the creation of duplicate items or to reconcile with an existing item based on certain criteria. For more information see section. For more information see section Item Reconciliation in Configuration Categories.
NOTE:If there is more than one configuration to the same ZENworks or an older configuration is deleted and a new configuration is created pointing to the same ZENworks, then you might end up with duplicate items, if reconciliation is not enabled or reconciliation criteria is not met.