This unable to migrate warning message indicates that the virtual machine has a device that is disconnected and pointing to an image that is not accessible on the destination host. In vCenter an error like: migration compatibility warning: Device uses backing which is not accessible appears.
- This warning can be solved, if you are using an image file (ISO, FLP, etc.) and not a physical device, unmounting the device how outlined by VMware Knowledge base.
Posted in: VMware vSphere