When I get the dropdown window under the "Family Trees" menu in Ancestry.com it lists all of my trees twice. Here is where I believe the problem started: I got a new computer and I reinstalled the FTM software & copied my data over to the new machine. Since then I have synced my trees to Ancestry. (I always manually sync my FTM and I only sync "to" Ancestry; NEVER "from.") Has anyone ever had this happen?

For now I need to know:
1) How to prevent this from recurring..
2) Would the solution be just to delete the older family trees in Ancestry (the ones that have an older sync date)?