From the main FAQ: "9. How many computers can I use VEGAS Pro on? You can use VEGAS Pro (14.0 and later) simultaneously on 2 devices. There are 2 ways to deactivate a device so you can activate a different one:
Visit your MAGIX account > My Products > Show More Details > Deactivate. This option can be used only once a month.
From the VEGAS Pro Help menu choose Deactivate the Software on this PC. This option can be used as often as you wish. An internet connection is required."