I had a handful of VMs throwing the same error. Shutdown the VM. Open Configuration for the VM (the gear). Select "Hardware" Tab / Select "Hard Disk 2" in the left side bar, click on the minus "-" sign at the bottom to delete Hard Drive 2. In each case the virtual drive had been pointed at the installation volume which had been moved or deleted. I looked all over for the answer, but eventually figured it out myself.
