LRC sync is constantly trying to download 103 photos from an iPhone I no longer have. How do I purge these items from sync without deleting all of my other synced data. I already tried resetting the sync data.
Login to your cloud account using the LrWeb app in any browser window (go to lightroom.adobe.com and login). That gives you a direct view into what's happening with your cloud catalog. Look below the All Photos container in the left-hand panel to see if there's a "Sync Errors" album showing there, which may contain those 103 photos that Classic is trying to download. If they are there, you should be able to delete them from the LrWeb interface, without affecting all the other images in the cloud.
Even if there isn't a "Sync Errors" album, you may still be able to see the failing 103 images still showing as "syncing" in the All Photos grid.