It shouldn't be necessary to backup all of your images again because the images are not part of the catalog. The only thing that should have to be backed up is the new catalog.
Jim, are you saying that you do not back up your images?????
I can't imagine not having a back up of my images.
Of course, I back up the catalog almost everytime I close LR but I'm talking about have a mirror image so that if the working HD dies, I can plug in the other HD and I'll have both catalog and images since the last full backup.
No, I didn't say that I don't backup my images. I said that your images are not "in" the catalog. They are in folders on your hard drive, and the catalog points to the images in those folders. When the catalog is backed up, Lightroom backs up the catalog only. It's your responsibility to devise, organize, create, what ever you want to call it, your own backup scheme to backup your images.
I seemed a little testy and I apologize. I do really need help because with the new LR my old scheme is leaving a lot of questions. I'm on a PC. Because of travel I've had my working catalog and images on an external drive(source). I back that up to another external drive (target). I've been using Vice Versa Pro with the mirror image option to back up the entire Pictures folder that includes my (LR) catalog and (Working Library) images. It has worked well for me for some time. However now with the new LR when I go to back up it shows about 850MB in the source and 0MP in the target for "newer files changed." I've compared both the LR catalog folder and the working library folder. The 850 MB "newer files changed" is in the LR catalog folder. I realize that you may not be familiar with Vice Versa Pro application but do you have any thoughts on this. If it actually writes 850 MB to the 2 TB external drive it will be in overload. Even if it erases the "older" 850 MB of data before it writes the new, I'll be hanging out there for a while until the "newer" LR CC files are written. I'm one of those people who can drive the car and have routine maintenance done but I don't understand how some of it works.