In the process of moving my lightroom catalogs to a different folder I deleted the "mobile downloads.lrdata." I have a backup some weeks old but I wan't have access to it for a few more weeks. Even though the pictures are still there in Lightroom.Adobe.com and still exist in Lightroom on the phone that took them, my Lightroom catalog on my mac shows the pictures as missing. How can I restablish links between my Mac and the photos in Lightroom.Adobe.com?
You misunderstood what Lightroom is telling you. Lightroom shows the pictures as missing on your local computer, not in the cloud. They are missing because you deleted that .lrdata file where they were stored, so you can’t reconnect them until you’ve restored that file from the backup.