Additional VMDK in VM Folder on Datastore

Hello All,

I received a disk space notification from one of my hosts today.  When I dug deeper, I found that there are additional .VMDK files that have appeared with my virtual machines.  For example, I have a VM running Windows Server 2008 R2 with one 450GB virtual disk.  In the same folder as the (servername).VMDK there is a (servername)_1.VMDK file that is 300GB.  No snapshots have been taken of this VM.  The last modified date on the _1 file is a couple of months old.

Any ideas on what would cause a VMDK file to be generated like that?

Thanks in advance -