When try to migrate the Account Hierarchy, system throws below error message:
Instance with the same key already exists
The cause for the issue is that there is already a Account Hierarchy exists in your system with same ID and hence it is not possible create another hierarchy for the same combination. This can be verified in the Account Hierarchy view of Business Partner Data work center.
The system works as expected
KBA , account hierarchy , AP-RC-BCT , Business Config. Tools (SAP Business ByDesign , How To