The main difference between Adobe Lightroom and Adobe Lightroom Classic lies in their workflows and storage. Adobe Lightroom, often referred to as Lightroom CC, is a cloud-based photo service designed for easy accessibility across multiple devices. It automatically saves all photos to the cloud, allowing for seamless editing and sharing. Adobe Lightroom Classic, on the other hand, is a desktop-based application with a more traditional folder-based workflow for organizing photos. It is suited for more advanced photo editing and requires manual management of photos and backups.