When trying to remove a shared field from a Vault document type, an error occurs: Field is referenced as a controlling field on related document type/subtype/classification.
The field trying to be removed is a parent to another field in the Document Type.
To remove the field, there is a dependency of the child field on its parent field. Remove the child field from the Document Type. Once this is completed, the parent field can be removed without issue.
- Vault Help Documentation: Vault Help