When you try to Apply a previously saved Checkpoint (snapshot) to a virtual machine in Hyper-V running Windows Server 2016, Windows 10 or Windows Server 2012 R2, a bizarre error message consistently appears even with full administrative rights on the machine:
Virtual Machine Connection
The application encountered an error while attempting to change the state of ‘virtmachine’.
‘virtmachine’ failed to change state.
The operation is not supported.
If restarting the “Hyper-V Virtual Machine Management” (vmms) and “HV Host Service” (HvHost) service does not help, a cold machine reboot should fix this rather strange issue.