I have these problems all the time. Usually they are because somebody is listed with multiple parents or wives and husbands are listed twice. Check that children are also not duplicated as well. This usually occurs when you merge different databases made by different people into one. Even the slightest difference in names or relationhips can "foul things up good". The problem can usually be traced back one or two generations from where you get the duplicates showing up. Also check that "cousins" did not marry. I have this problem in my tree all the time. Also if grandparents, 2nd spouses etc. are listed as "adoptive parents" etc this will give funny results. Also run a thorough check of your database using the "file repair tools". A glitch in the file can really foul things up. Legacy does not like "GAY" relationships. If you have a glitch where two people of the same sex are married it will give errors. This often occurs because when you add people the database usually defaults to "Male". So "Sarah Jones" who married "Bill Watson" may show up as husband and husband even though Sarah was a girl but you forgot to give her the right gender. Clumsy use of the "merge" button can also lead to miserable problems. If you have 3 "Tom Jones" with no dates or other details and you accidently merge them into one, Grandpa Tom can end up being his own grandson Thomas.the 3rd. Legacy has NO "UNDO BUTTON" which makes life miserable if you make a boo-boo. My database runs 300,000 people all of whom are "related" in some way. The 3rd 3x removed cousin who marrried the 4th g-aunt makes a mess of things. It's just like the old song ."I am my own grandpa" Nelson Denton