LR 5. On Mac When I tried to export a newly created catalogue to HDD, Dropbox "lost" all my photos in the library. When I rebooted, LR started up very slowly, and when it opened no photos are seen and no catalogues exist. Along the way I had tried Unsuccessfully to create a new folder in Dropbox into which I was going to export the catalogue to. I am dead in the water and don't know what to do. I am backed up with time machine. Any help is appreciated as I have no access to phone support and live in a small town without tech support.
Would suggest you to go to File menu > choose Open Recent and check if the you are able to access the catalog that contains all edits.
Or, you can search for .lrcat files on your machines and check if it results the required catalog as exporting from catalog does not cause the images to be deleted.
Restore whatever you lost from Time Machine.
Or use your operating system's search feature to search for all files whose name ends with .LRCAT. Double-click on each one found to open it in Lightroom.
Bingo! Thank you. I am up and running again!