Cakewalk lets you legally install their software on more than one machine. Legally, you can't use more than one machine at a time - as Mr. Jonesey points out you run out of appendages.
Cake issues you a serial number but also a registration number. I don't know if a registered machine checks in over the net to its master or not. But the system is designed to keep track of your numbers. That stops you from selling your old copy of SONAR more than keeping it off your 2nd or 3rd machine. If you sell SONAR, you have to give the buyer your reg number but they won't be able to update it. The only way to do that is to give your Cake account number. The system works pretty well w/o all the problems of locks or iLoks.
Up until a few years ago there was always someone coming onto the forum wondering why their 3rd party purchase of SONAR wouldn't work. They bought a cheap copy of SONAR w/ serial number but no reg number and it wouldn't work after 30 days. You get what you pay for. Or less.
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