Posted by This error occurs when you rollout a Generation 2.
Issue occurs because the Bootmgfw.efi file is set as the first startup device that the VM tries to start from, instead of the .vhdx file which contains the operating system.
Solution:
To resolve this issue you must change the firstbootdevice in the template.
Open a Virtual Machine Manager Command Shell:
Get-SCVMTemplate -name “Windows 2012 VM Template” | Set-SCVMTemplate -FirstBootDevice “SCSI,0,0″
Change multiple GEN2 templates.
Get-SCVMTemplate | where-object {$_.FirstBootDevice -cnotcontains "SCSI,0,0" -and $_.Generation -eq "2"} | Set-SCVMTemplate -FirstBootDevice "SCSI,0,0"