I did a sync to my Family Tree Maker several days ago; I don't know if I clicked an incorrect option (if so, this shouldn't be allowed), but the result was duplicate, triplicate and, in some cases, up to six replications of some individuals in the ancestry.com tree for a total of over 1000 repeated people. Many pieces of information, especially residence information were also duplicated within the individual records, ditto for stories and photos. Before I started repairing it, my tree was a horrendous mess. It has taken me four complete days of work to get it straightened out and I'll address the duplicate residences, etc. as I find them. Needless to say, I won't be using Family Tree Maker in the future.