It is compatible with Windows 10...I am running Windows 10 on two laptops with no problems, but I did need to download the dongle upgrade for Windows 10 in order for the program to recognize it...here is the link for the dongle upgrade...it indicates it is for both MBX 4 and 4.5 versions...Your dealer is full of crackers...tell him to check the Janome website...Make sure you read the installations instructions....