Confused by your comment about "turning off iphone sync in Classic"....it's not possible to sync to specific devices, you only ever sync to the Adobe Cloud (and that applies to all the LRCC apps as well). Having said that, here's how it all works: 1. There are several "cloud-centric" apps under the "Lightroom CC (LRCC)" banner, such as LRCC on the desktop, LRCC on phone/tablet, LRCC Web. These all operate in the same way...specifically every image that you add (import) to any of these apps will be uploaded as the full original to the cloud. From there, they will be available for download to the rest of the LRCC apps, and you have some control over whether you download the original or a smart preview (though thumbnails are always downloaded). Subsequent changes (edits, certain metadata) made using LRCC on any of the devices will sync via the cloud to the other devices. One point here is that you don't have to store the "LRCC on desktop" originals on the local system. 2. LR Classic is NOT an equal member of the cloud syncing. For a start, not all images added will automatically sync, the user has to decide what and how to sync them. When images are sync-enabled, only Smart Previews, not full originals, are uploaded. And while all edits made in Classic to synced images WILL sync to the LRCC apps, not all metadata does....notably keywords and location data do not sync between Classic and the cloud. One last point, if Sync is enabled in Classic, EVERY image that is added to the cloud from any of the LRCC apps will automatically be downloaded (full original) into Classic (and will be stored on you local system in the default location, though you can change that location using Classic Preferences>Lightroom Sync tab). Hopefully, that should clear up some of your confusion, but from that you might need to think about how you use (or even IF you use) LRCC for desktop and LR Classic on the same system. I do, but in LRCC I have elected NOT to store a local copy of the cloud originals, so I don't end up with the sort of duplication you're concerned about. On my main system, Classic is my main app, so ALL my image assets eventually end up in the Classic catalog and file structure, and are backed up accordingly as they always have been. The main virtue of LRCC'c could storage (for me) is not so much that my files are backed up, but rather that they are available to me wherever I am on whatever device I have with me at the time. Hope that helps.
... View more