Snapshots are great for maintenance and rollback, but are not for backups. After you don't need the snapshots anymore, delete them so that changes are merged back into the main VHD. Otherwise, in the event of disaster, you will have to restore the Hyper-V host and configuration so that changes stored in snapshots are not lost (instead of just restoring the VHD file to any other Hyper-V host). Another option if you find yourself in this situation: How to manually merge Hyper-V snapshots back into one VHD