I quit Lightroom as I was quitting all my open application and it asked me if i wanted to back up the images before quitting as usual. Once the application had quite, moments later i went to reopen it and a brand new empty catalog appeared, and searching for the catalog on my Mac was unsuccessful as well. HELP!! I know the images aren't gone, and they're on my computer - but they aren't organized. What should i do? Also when i open Lightroom, and open the optional catalogs, its gone.
What did you search for? Search for .(DOT)lrcat (that's a lower case L not an i).
In LR select File>Open Recent and see if you have more than one listing.