Whoops, the full question should read...
" I've lost all my most recent work after Lightroom crashed and feel that I'm now in a real muddle. I hadn't backed it up as I was still working on it when Lightreoom crashed and I had to force quit to close Lightroom down. When I re-opened it the work was still there but I was unable to back it up. I was asked various questions and seem to have installed an earlier back up so all the current work has vanished. Is there any way of getting it back? Would Time Machine work? I'm using a Mac OS X 10.9.4."
First, try File->Open Recent and see if any of the catalogs listed there have your work.
If that doesn't work, then you should have your operating system search all of your hard disks for files that end in .LRCAT and double-click on each of those files to open them, and see if any of those catalogs contain your work.
And also very important, from now on you MUST make regular, automated backups of your catalog file and all photos. No excuses.
Hi, thank you so much for your prompt reply. Unfortunately neither of these options brings up the catalog, only the one from the earlier back up I re-installed. I think I panicked when it wouldn't back up after the force quit. Lightroom didn't actually say the catalog was corrupted, just that it was unable to back-up and gave me the option to re-launch from an earlier back-up. I wish I hadn't done that and looked to try and export the work I had just done first at high resolution. Just before it crashed I had exported all the images to a folder and up loaded them to a gallery on my web-site but they are only low resolution. I just wonder if, as they had actually exported through Lightroom, whether that would mean you might know of another magic solution? You are so right about the back-up. I'm normally pretty good at that, but it only takes that one time, as I've heard so many times before, and now know only too well. Any other ideas gratefully received!