A Vault in Mylio Photos+ is a device that stores a complete copy of all your files and photos. It's recommended to have multiple vault drives for added security. Devices designated as Vault allow for automatic protection of new media, syncing between devices, storage optimization, and easy access to full-sized original images. You can use computers, external hard drives, or cloud services as Vaults. When using cloud services, Mylio Photos+ can encrypt your cloud data for added privacy and security.