Indeed it exists on both AL 2 and AL 3. But LR does not show AL 3 at all.
I realize that I clicked to tell LR where the missing files are, but I didn't know LR would move the files rather than just link them up with the info in its catalog.
Thanks again so much for your help!
You keep saying that LR moved the files to AL2, which I've already said is not the case, so perhaps I'm not explaining things very well....so I'll try again as it's important you understand this:
Initially you had a drive called "OWC Mercury Elite AL Pro" which contained some 35k+ images that had been imported into Lightroom. You then decided to rename that drive to either AL2 or AL_3 (I'm not sure exactly which), but after doing that Lightroom has now lost contact with those 35k images for the simple reason that the OWC Mercury etc. drive is no longer online. Lightroom doesn't know that you've renamed it to something else, it just doesn't see the original drive so all 35k images are now reported as "Missing or Offline".
At this point it appears you've clicked on one of the missing images in one of the sub-folders and used the "Locate" function. When you use this option, Lightroom doesn't go off and search the system for the missing file (as some users think), instead all it really does is ask the user to tell it where the missing file can be found. This is done using the file browser that opens, and it would seem that you've used that browser to point to the file on the AL2 drive, at which point Lightroom verified that the file matched the info in the catalog, checked around and found another 129 missing images in the same folder on AL2, and so updated it's internal tables and as a result added the AL2 drive and the folder and the images to the Folders Panel.
No files were moved, they already existed on AL2, only the catalog was updated.
AL_3 won't appear in the Folders Panel until such time as you either import some pictures to/from that drive, or if you had "located" the missing file on the AL_3 drive instead of the AL2 drive (then obviously it would be AL_3 you now see in Lightroom instead of AL2).
And that almost brings us to the next issue: when we come to relink those missing 35k images from the OWC Mercury drive, which drive do you want them relinked to? As I understand it, the images exist on both drives, so at this stage you can choose which one you want to use as the "prime" LR images drive (with the other presumably being a backup)? Or was it your intention to spread your images across both drives?
However, before we get that far we have to deal with another issue. According to the LR Folders Panel, below the "!JWW LR & Bak Photos" folder are three sub-folders: "!2013", "2012" and "J Photos 2012 bk", containing respectively 8452, 27072, and 83 images. However, in the Finder screenshots I cannot see that "2012" folder at all, and given that Lightroom thinks there are 27K images in it, we need to understand where it now is. Do you know, and if so can you show me?