I am trying to consolodate all of my scattered images into Lightroom CC. To avoid any image loss, I've created massive duplications. I currently have 731,000 images in the catelog, but probably only about 100,000 unique images. I had planned to use a separate duplicate identifier to remove duplicates.
As I understand the workings of the catelog, once I do this, the catelog will still register 731,000 images, but many won't be "found". I have come across many ways to "find" these images, but that is the opposite of my goal.
I haven't (yet) found a way to tell Lightroom to rebuild the catelog with the images that remain in the folder. Please help.
Once the images have been added to the catalog, they have been added. That record has been added to the catalog which is a database. I'm sure you are aware that the image itself is NOT the catalog. The catalog is just a database that keeps track of where the images are located on your computer as well as what adjustments you have made to those images and what collections you have added them to and other stuff. When you were adding these images, did you choose the option to not import suspected duplicates? Are you familiar with proper importing procedures? Are you familiar with using Lightroom Classic or are you a new user?
"I haven't (yet) found a way to tell Lightroom to rebuild the catelog with the images that remain in the folder. Please help."
After the duplicate finder program deletes the files that it believes to be duplicates, you should be left with one copy of each image on disk. Then, in Lightroom Classic, Library->Find All Missing Photos, and then you can remove all of these missing photos from Lightroom Classic.
I would make backups of everything (all photos and your catalog file) before you do this, just in case. DO NOT SKIP THISSTEP. See, this is a really really really really really really really really important step, that's why I told you in bold and capital letters not to skip this step. If you do skip this step, I will have no sympathy for you.