I have a D-1 machine I love, both for stitching and the embroidery. When I purchased a new computer I found the Dongle was not compatable with the new computer. To up grade the local Viking dealer quoted $500. and the machine would be worth $500. I have not checked into it since as I have a newer Phaff machine. I would like to know though what you find out. The software I was using was the Viking Customizing and also Embird the format is HUS if I remember correctly. I still have and use the machine for regular sewing and design stitches.