Hyper-V spontaneously pauses all VMs

I experienced the same thing after the host blue screened. Could not start any of the machines that had been running just fine before. Just got the error message "'machine' could not initialize"

I restarted the host machine one more time, and now the machines start just fine.

Maybe this can help others, before resorting to other solutions.

Is the upstream physical switch port set to a trunk? It shouldn't be sending tagged traffic unless it is, or if it's explicitly configured to do so. If you could convince the admin of the physical switch to set the native vlan on the port to 2, your upstream traffic would make it there correctly, but you're still probably going to receive tagged traffic downstream.

My opinion: You're wasting time. If you're receiving tagged traffic, then you should just configured the right tag on all required ports physical or virtual on the HyperV host and call it a day. With 10 VM's this would take me all of about 15 seconds on a VMware machine, I can't imagine HyperV taking much more effort. Good luck finding a solution to it they way you WANT it, but I doubt it's going to happen.