Diagnosis
The system attempts to generate the external person ID in infotype0709 but determined the person ID &1 because of the generation ruledefined in Customizing.
However, this value is already being used for another person.
Since the external person ID must be unique, the value for this currentpersonnel number remains empty.

Procedure
Check the personnel numbers that use the same external person ID andcorrect the external person ID manually in infotype 0709.