I am not sure what you mean by "loading the missing photos in LR" . If you mean have I done a search via the text field for the file name, yes I have and I cannot find them in LR. As I mentioned the originals are still in location of the HDD where LR was accessing them from.
There are no previews showing up for the images in the original catalogue. How do I look for the previews in the catalogue?
Do you have a backup catalog.? If so try opening it
Also by "locating missing photos" I mean reconnect the missing pictures in catalog
Let me clarify a bit.
Catalog A resides on HDD A (external drive). I do not have previews in catalogue A for these missing files so I cannot relink them. I first imported the files from my camera card to HDD A.
On the same days as I imported them to HDD A I also exported some of the images to a new catalogue B on HDD B (actually the Mac HD) They must have been there for me to be able to export them to the new catalogue. They are all present in the new catalogue B (on HD B) but some of them are missing from the original catalog A on HD A.
I can see all the original DNG files on HD A.
As I created the second catalog on the same day as I imported the files to catalog A I do not have a suitable backup.