Hyper-V Storage Migration Failed

Whilst trying to migrate the storage location of a 2012 Hyper-V VM, you may encounter the following error:

Storage Migration “Operation not allowed for VM because Hyper-V State is yet to be initialized from Virtual Machine Configuration” (0x80070015)

To resolve the issue, simply restart the VM Management Service on the Hyper-V host by running the following PowerShell command:

Restart-Service VMMS

Then retry the migration and the task should complete successfully.