The Mac OS X disk (and any partition) is listed in Windows Explorer as a local hard drive, but it is not accessible. If you try to explore the disk, the follow message appears:
"You need to format the Disk in X: before you can use it. Do you want to format it?"
When using a Boot Camp-based Windows virtual machine, the Mac disk is mapped to the Windows Explorer as a local hard drive. The disk cannot be accessed from Windows because Windows sees the disk as being in use by Mac OS X.
To access the Mac disk (or partitions) from the virtual machine, use Shared Folders mapped to Windows Explorer as a Network Drives (Home on 'psf'):