A powered off VM on ESXi 6.5 will not power on and returns the error “Failed to power on virtual machine…. The attempted operation cannot be performed in the current state (Powered off)”.
(i.e. the VM cannot be powered on BECAUSE it is not powered on!)
Prior to being powered down the VM properties had just been modified. In this particular case it was immediately following a manual Ubuntu install and the install DVD (from a datastore ISO) was disconnected and the CD Drive switch to” “Host Device”. These operations were performed from the ESXi Web interface.
Repeated attempts to start the VM all fail the same way.
Unregister the VM, then locate the vmx file in the datastore and re-register it. The VM should now power on.