The Master Genealogist DOES NOT run well in 64-bit. I've been using it for years quite happily until I bought a laptop running W7 64-bit for my genealogy road trips. Most of the reports generate errors, filtering and sorting malfunctions, and random errors pop up here and there then never again. Go the the Wholly Genes forum and search for "64-bit" and read all the problems before you purchase TMG.