This is a new message beginning in 7.1. It results when all of the source records are mapped to Bypass because the system is no longer generating summary rows for those mapped to Bypass. The workaround is to set the Is Optional Data Load workflow setting to True which allows the user to complete their workflow when the import fails, without needing to complete the Import-Validate-Load steps. Another workaround would be to change your transformation rules to map the data to a dummy member you could create outside of your reporting hierarchies.