Today’s Question: I created a mess in Lightroom Classic by moving around my photo files from my computer instead of within Lightroom. I ended up just starting over by creating a new catalog and importing my photos. Lightroom Classic is now asking me to sync my catalog, but I fear my original catalog probably still exists and don’t want duplicates, etc. Should I delete existing catalogs before I sync my newly created one?
Tim’s Quick Answer: You can only have one catalog synchronized to your Creative Cloud account. I suggest checking the status of currently synchronized photos before enabling synchronization for your new catalog.
More Detail: In Lightroom Classic you can enable synchronization for individual collections, which will cause JPEG previews for the images in those collections to be synchronized to your Adobe Creative Cloud account. That enables you to view and update those synchronized photos using the Lightroom mobile app on a smartphone or tablet, using the Lightroom cloud-based application, or accessing Lightroom via a web browser (https://lightroom.adobe.com).
Because of the way synchronization works in Lightroom Classic, for many photographers it is perfectly safe to change which catalog is being synchronized. However, there is a risk of losing images depending on your specific workflow.
If you have captured new images using the Lightroom mobile app or have imported new photos into the cloud-based version of Lightroom, without having imported those photos into a Lightroom Classic catalog, changing synchronization can cause photos to be lost. That is because the source of those photos will have effectively been discarded by changing the catalog that is the source for synchronization.
I therefore recommend logging in to Lightroom in a web browser at https://lightroom.adobe.com to confirm that no photos are synchronized to your Creative Cloud account that aren’t accounted for on your local hard drive. As noted above, that would include photos captured using the Lightroom mobile app or imported into the cloud-based version of Lightroom. If any such photos exist, you would want to download them to your local storage first, so they can be imported into your new Lightroom Classic catalog.
As long as all photos have been imported into Lightroom Classic and synchronization has only been used from Lightroom Classic to make photos available for sharing elsewhere, it is safe to enable synchronization for your new catalog, which will disable synchronization for the catalog that had previously had synchronization enabled.