RichardNYC: My question "Why would Family Tree Maker Version 10 and Family Tree maker 2010 Platinum (Version 19) be compatible with W10 and Family Tree Maker 2010 Deluxe (Version 19) not be compatible?"
Was not a question about why Version 10 and Version 19 are compatible, BUT why the Platinum version 19 is compatible, and the Deluxe version 19 is not.