Organizer says that my photos have already been downloaded, but they do not show up. I have not found an answer in any of the hours I have spent trying to find an answer. I also show no catalogs when I got to the catalog function.
If you go to File>Catalog and see no catalogs listed, first check the three radio buttons (Catalogs Accessible by All Users, etc). If you try all three options and still nothing shows up, then your current catalog is in a custom location other than that which is currently selected. If you need to know where your catalog is stored, just go to Help>System Info and look under the Current Catalog header.