When importing Supplier.csv file we see the following import error:

You cannot associate a common supplier with multiple partitioned suppliers. The partitioned supplier XXXX:YYYYY cannot be associated with the common supplier ZZZZ, because this common supplier is already associated with AAAA:BBBBB.
Error executing trigger IntegrationPostLoad on [ariba.common.core.Supplier [BaseId 316300862255 AAu4AE4EmlACMv 41b1d7an.d07z20]] with data ...

In order to resolve the issue you must break the link between the Common Supplier and Partitioned Supplier.

1. Reactivate the Partitioned Supplier currently linked to the Common Supplier by importing them in the Supplier.csv and Supplierlocation.csv.
2. When you import these suppliers leave the Parent.UniqueName field in the SupplierLocation.csv blank and the SupplierIDDomain and SupplierIDValue fields as blank in the Supplier.csv. This will break the link between the Common Supplier inactive Partitioned Supplier.
3. Once you do the above you should be able to run the regular supplier import without error.

This error appears when the Common Supplier you are trying to link to in the import file is already linked to a different Partitioned Supplier in SAP Ariba Buying and Invoicing solution.

Core Procurement > Core Administration > Core Administration Supplier Management