In order to avoid the error message when you try to install Hyper-V role on a Hyper-V VM through GUI, you will have to run several Powershell commands:
- First, you need to change your Powershell execution policy script to at least Remote Signed: Set-ExecutionPolicy RemoteSigned
- Then you will have to install Hyper-V role: Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All -NoRestart
- This step is to install Hyper-V management tools: Install-WindowsFeature RSAT-Hyper-V-Tools -IncludeAllSubFeature
- (Optional) Finally, you can also install Failover Cluster and MPIO feature: Install-WindowsFeature RSAT-Clustering,Multipath-IO -IncludeAllSubFeature
Then you will just need to reboot your VM to complete the installation process. But don’t forget, you will be able to create an Hyper-V failover cluster and create highly available VM but you will not be able to start them.