The Schema Wizard stops with a message:
Object with the same name already exists in the database: Buildings
Where 'Buildings' is the name of a feature class in the UML model.
Feature classes owned by the same user must have unique names in the geodatabase, even if they belong to different feature datasets.
The Schema Wizard will not be able to create a feature class if the name is already used by an existing feature class.
This may occur when the UML model is reapplied and the existing feature class is of a different feature type.
Delete or rename the existing feature class, or rename the UML feature class to avoid the name conflict.
If you intend to reapply the schema to update an existing feature class, make sure the UML class and the existing feature class have the same feature type. For example, both are complex edge feature classes.