When installing Messaging Gatway (SMG) on a new Hyper-V VM, attempting to boot from the mounted SMG ISO image file results in a message that no operting system was loaded.
No operating system was loaded. Press a key to retry the boot sequence...
When creating the Hyper-V virtual machine, "Generation 2" was selected rather than "Generation 1". Generation 2 virtual machines have additional boot security and image signing which prevents SMG from being installed and booted.
Recreate the virtual machine and select "Generation 1" in the Add Virtual Machine wizard.