Assuming he isn't an apprentice, on his Employment tab click the Apprentice button and check whether a start date has been put in there.  If he was an apprentice previously, enter the date his apprenticeship finished.  if he wasn't, make sure both fields are empty.   

Assuming he isn't an apprentice, on his Employment tab click the Apprentice button and check whether a start date has been put in there.  If he was an apprentice previously, enter the date his apprenticeship finished.  if he wasn't, make sure both fields are empty.