I have several VMs running in Hyper-V on Server 2016 that we shutdown remotely and then reboot the host. They're all configured to automatically restart upon the host's reboot, with a startup delay varying between 30 and 600 seconds (each VM is different).
SOME of the VMs will happily restart. SOME of the VMs do not start at all.
Looking in the Hyper-V event logs, there are absolutely no errors or complaints logged at all. It's as if it never even tries to restart those VMs.
We're not doing anything weird storage-wise; all VMs are using the same HDD storage area. We're well within the available RAM of the host machine (128GB). There's nothing odd about their boot options. Several of these VMs are identically configured to each other, and one will start while the other won't.
What in the world is going on?