Not so, you can run as many Hyper-V VMs at once as you want (assuming you have enough resources on the host).
If you are failing to run more than one at a time then this is an error - it certainly works fine for me. What error message do you get (perhaps opening a different thread would make sense...)
I wasn't running into any particular error but only seeing the message of not allowing multiple instances. With 16gb of memory I wouldn't worry about running out of resources like I did previously on an old case with only 4gb I used back when testing 7. I planned the present build out to allow for expansion and now find three versions later that 10 doesn't require anything more then 7 does! MS made progress with the MinWin kernel despite 10 being a larger dual platform OS so it won't take more to run it.
Actually I generally wouldn't be planning to be running multiple VMs anyways while the thought of being able to fire up a second or third when busy with the first was an idea. Since the desktop state is preserved on VMs while that would take sleep or hibernation for the host OS shutting one down to start up another goes much quicker then restarting the system to boot into the other side of the dual boot here. I still need a bit more time with Hyper-V itself however.
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