Quick explanation: the dongle that comes with Viking (and Pfaff) software acts as a key to unlock and use the software each time the software is run - the software will not run without the dongle attached to the computer. If a dongle breaks, it has to be turned in to the Viking dealer before a new one will be sent from Viking to replace it; according to my dealer, a lost dongle will have to be replaced through the purchase of new software. Breaking or loosing a dongle is a serious problem.
The dongle issue is the # 1 reason I will not purchase Viking software; the fact that you have to pay a yearly fee for support is reason #2. When I bought my used D1, I didn't get any software (not even Disk Manager, which is used to transfer designs to the disks for the machine) so I researched software options. My D1 uses floppy disks, so I can use Embird for 1/5 the price of the Viking software; no dongle, free support and an all-around great program. Embrid will not work with the D1 USB machines, tho.