This is a duplicate post.
(For some reason, your question appears as a duplicate post. not sure if you can see my answer, so here it is again)
re: "LR won't accept them"
Here are some screen shots that may help explain what is happening:
This is the old external drive. My parent folder is "ALL PHOTOS GO HERE". Please note the 7 subfolders, 6 of which contain further subfolders, that were left behind:
As you can see, the old drive still has almost 5000 photos of various formats remaining. If I try to move any of them using the LR drag and drop, either as parent folders, subfolders, or as individual images, I get an error message that says the file or folder already exists in (the new) location. LR did actually move the folder, but is not showing them in the new location.
TO BE MORE PRECISE:
Here is the NEW external drive. It contains all the subfolders that I intended to move and some of the tertiary subfolders. For example, the 2003_PHOTOS folder shows AMEXIT with 4 subfolders:
and here is the old HD, showing AMEXIT in the 2003_PHOTOS folder with many subfolders remaining:
Some of the folders, like RICHMOND1, above, were duplicated but hold no images.
Here is the error message that appears when I try to drag any of the above folders into the new HD:
according to LR's directory listing above, "ROUTE95 2" does not exist in the 2003_PHOTOS subfolder of the new HD. But when I click on "show in finder" in the error message, those subfolders and their photos are indeed in the new HD, even though LR is hiding them from me.
I have even made sure these photos were not corrupted: using the finder and photoshop, I have successfully developed several of the DNG files that now show up in the new HD.
( curiously the LR import function shows them grayed out in the OLD HD, not the new HD. The import button is not present in the import dialogue, because they physically already in the new HD.)
It sounds more confusing than it is, and I hope my explanation is clear. Any thoughts/actions are much appreciated!