Found the solution in another thread. You have to add this to your VMX file when using VMware Workstation 12.5:
disk.EnableUUID=“true”
- Shutdown your Rockstor NAS instance.
- find and edit the VMX file with Notepad or Notepad++
- Scroll to the very end of the file and paste the above line into the file.
- Save the VMX file.
- Start your Rockstor NAS instance. You should now see the drives you added when setting up your VM.