Do you have any filter turned on by any chance?
The best way to change folder organization is through within Lightroom instead of doing it outside Lightroom.
Since, you have done it outside Lightroom, best way for you would be to relocate the missing images.
Also, check if you have a backup Catalog and relocate missing images from there if you have all the images here.
Refer this article : How to find missing photos in Photoshop Lightroom
Are there question mark icons on your folders? Are there exclamation point icons on your photos?
Since the photos have already been imported, then importing again (or synchronizing the folder) will not help and would make things worse if you actually were able to do this. You need to find the photos in your Lightroom. How to do this depends on the answers to the questions above.
it would also help if you showed us a screen capture of the problem.
There are no question mark icons on the folders. The folder name is grayed out and next to it is an elipse - '...' - which I understand is Adobe's way of indicating that the process is working or counting. When I click on the folder name no photos display.
There is no exclamation point on the photos because they won't display in Library. The only place they do display is on the Import screen, but there they are grayed out:
Please let me know if I can provide any more info, and thanks again for your help.
I want to see the Library Grid view, are there exclamation points there?
What happens if you go to Grid View, click on All Photographs, turn off all filters (Cmd-L once or twice) and then scroll all the way up and down, do you see your photos then?
Well that's good news. To find the folder they are in, you can right-click on the photo (I think on a Mac it is Ctrl-click), and select Go To Folder In Library.
This will highlight in the Lightroom Folder Panel the folder that this specific photo is in. You may have to scroll up or down to see the highlighted folder. With any luck, your folders will still be intact, with all desired photos, just in a different drive/folder location than you thought.
From there, you could move the photos back to the desired folder, or ... if you don't mind me making a suggestion ... don't use folders any more to classify and organize and search, use keywords and other metadata to organize and search, and then you won't have to worry about the photo being in the "wrong" folder because there are no "wrong" folders.
Okay, right-click (Cntrl-Clik) on a photo and select Show in Finder. That will also tell you what folder Lightroom thinks the photo is in.
Based on your last screen capture, there are likely two copies of this photo, one in the folder YOU think it is in, and one in the folder Lightroom thinks it is in.
If that is the case, you'd have to delete the copy in the folder YOU think it is in (using your operating system) before you can do the move in Lightroom. (Try this on one photo first to see if it works, in fact don't delete the one photo from the folder YOU think it is in, but instead move it to your desktop until we are sure this will work).
Lightroom and I both think the file is in the same folder, but it seems that somewhere along the way I managed to create the folders twice in Lightroom - once with the parent folder listed and once without it. On the top left of the screen below you can see the folder "Alaska" under the directory '07 July', and it is all the subdirectories under 'Alaska' that have the photos that I can't see. Toward the lower part of the pane, you can see the 'Alaska' directory again, with the same subdirectory structure under it. However, when I right-clicked on the lower 'Alaska' folder and tried to show the parent folder, I got the error message that you see. Lightroom won't let me remove either one of the duplicate folders, and I can't delete the files inside because I can't see them. Do you think there is any way out of this mess?
Okay, so I think I have seen this problem or a similar problem reported for Mac computers before, where the folder appears twice in the Folder panel, corresponding to a single actual folder. Since I am not a Mac person, I do not know the answer (if there is one). I hope someone else will come along with ideas.
Again, I state my advice that if you organize and search by keywords and other metadata, then there is no problem. it ddoesn't matter what folder you or Lightroom thinks the photo is in, because you are no longer using folders to find your photos.
Thanks for trying to help. I'll keep searching . . .
Could you change the folder display option, so that it might make it a little easier to see what's going on? Click on the "+" sign at the right-hand side of the Folders Panel header, then in the resulting context menu change the Root Folder Display to "Folder Name Only", then repeat the screenshot of the Folders Panel (so that both of the "Alaska" entries are showing).