For Named User or Designated Computer licenses then VM are not counted as separate machines . For those licenses , using a VM has the same status as starting up another copy of matlab on the same machine .
That said , to run a VM you need a MAC address associated with its virtual internet interface . Matlab is going to compare that mac address to the license file and reject if there is no match. Typically you need to use a different mac address than the host is using so that the vm can distinguish whether the packets are for the host or the VM . I know that Parallels has an option to share mac address but I seem to recall that it works by using a different mac internally and translating in the virtual interface for packets going off host. I have not experimented to see how it interacts with matlab licenses .
What I do for simplicity is assign the same mac address to all my Windows vm and a different mac for my linux vm both different than my host mac. The license I am using permits up to 4 activations so that permits me to use osx plus Windows vm plus linux vm simultaneously .
If you were dual booting then that would not be a license problem as you do not license per os, only per activated machine no matter which os.
If you have a Student license or Home license then you are restricted to one activation and at that point the Mac address used inside the vm becomes the challenge .
