You can delete a snapshot or an entire snapshot subtree. A subtree is every iteration of a snapshot that was created, starting with the root node containing the original snapshot. When you delete a snapshot, as opposed to the snapshot subtree, you are deleting only the latest version of the snapshot.
In Service Center, click Status > Service Modules.
Click the Hyper-V link.
In the Managed Sites table, click a site name.
In the Managed Hosts table, click a host machine name.
In the Guests table, click the name of the virtual machine on which you want to delete a snapshot.
Scroll down to the Available Snapshots table.
Beside the snapshot you want to delete, click one of the following:
Delete
Delete Subtree