Lightroom earlier crashed as I was trying to save out a file. I ended up having to shut the computer down but when I rebooted and tried to open Lightroom, a window opened with the message "The Lightroom Catalog name "Lightroom Catalog" cannot be opened because another application already has it opened". I have the option of changing to a different catalog which allows me to open Lightroom but I don't have access to my files! No other applications are open on the computer. Any suggestions?