This issue has been covered many time on this forum and I'm surprised you didn't find anything when you first searched before asking however here are the facts...

Fact 1. Apple doesn't guarantee the BSD Name of a Disk between reboots.

Fact 2. VMware unfortunately and inexcusably was unaware of this when they designed Fusion and as such when OS X assigns a different BSD Name to a Disk then it previously had and when this Disk has a Boot Camp partition that has already been prepared to run as a Virtual Machine then two or more entries for the one Boot Camp partition can and will appear on the Virtual Machine Library in all versions of Fusion to date.

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This is more prevalent on with a Mac Pro however I've experienced it with a MacBook Pro and especially when having external drives attached that have a Boot Camp partition on them. On a Mac that has a single hard drive and only a partition for OS X and a partition for Windows it's less likely to happen compared to the Mac Pro which often have more then one internal drive however I have experienced it on a MacBook Pro in of by itself however it is more likely to occur when multiple hard drives are in play.

AFAIC Until VMware corrects this issue it is not worth using the Boot Camp partition as a Virtual Machine and I went so far as to, with Fusion closed, rename "/Library/Application Support/VMware Fusion/vmware-rawdiskCreator" so Fusion would stop enumerating the Boot Camp partition and placing an entry on the Virtual Machine Library. I then deleted the "/Users/${USER}/Library/Application Support/VMware Fusion/Virtual Machines/Boot Camp/../Boot Camp partition.vmwarevm" Virtual Machine and opened Fusion and deleted the Boot Camp partition entry on the Virtual Machine Library and will not use it on the Boot Camp partition until VMware fixes it!