I am seeing this behavior and I find it interesting.
After I close a Virtual Machine on VMWare-Workstation, even closing the VMWware-Workstation console I see lots of hard disk activiy on of the virtual machine.
I have seen this in the VMDK and in the VMEM files as you can see here.
¿Why could be this happening?
I dont think is the Antivirus software neither superfecth because I enable it only to fetch the boot files.