Copy a Mac virtual volume

Apple has wrecked several apps in recent OS upgrades and I need to access an older version of OS X (Mountain Lion) and related files without having to reboot.
Is it possible to take that existing startup volume and import it as a virtual machine?
If not, can I create a virtual volume, install Mountain Lion on it and use Apple's migration assistant to import the settings and content?

 

Hi, you may create a Virtual Machine of Mountain Lion and then import settings and content. Parallels Desktop 11 for Mac supports Mountain Lion as Guest OS. Refer to this article for System Requirements.

 

Can't migrate because physical drives are unavailable from within the virtual Mac volume. Sharing is set to see the drives, but they can't be found. Note that the option of installing the OS via the restore volume doesn't work - Parallels defaults to a full download.