If you are a Windows Insider you may see that some of your virtual machines are missing from Hyper-V Manager on Windows 10 – Build 10547. Bad news, there is a bug in this build. Good news, the VMs are not lost – and they are easy to get back. The problem is that this build has a registry key that tells it it can only see version 5.0 virtual machines:
This value actually needs to be 6.2 (not 5.0). You can either change this with RegEdit – or by running the following command from an administrative PowerShell prompt:
Set-ItemProperty -Path “HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Virtualization” -Name “CurrentVmVersion” -Value “6.2”
Once you have made this change you will need to restart the Hyper-V Virtual Machine Management Service. You can do this using Hyper-V Manager (Stop Service) or by running:
From an administrative PowerShell prompt.