Oracle VM Virtualbox cannot delete snapshot

When you try to delete the snapshot on a VM, you receive the following error:

 

Solution:

In Oracle VM Virtualbox Manager, Go to "File > Virtual Media Manager" menu, then select the [Hard Disks] tab and expanded the tree of the virtual disk under the problematic virtual machine.

Deleted one snapshot like the following:

 

Reference:

http://nicolasjolet.blogspot.hk/2012/02/virtualbox-not-allowing-to-delete.html

http://superuser.com/questions/1011325/virtualbox-windows-10-guest-resizing-snapshots-and-losing-activation

Oracle VM Virtualbox cannot delete snapshot