My images in LR 4.3 suddenly have been duplicated.

Question

All of my 20,000 images in LR 4.3 were suddenly duplicated.  All the adjustments, ratings,just as if I had selected all and clicked "Create virtual Copy".  Is there a way to eliminate duplicate images or undo this mystriuos process?  In checking, the second image is a copy of the JPEG image which I exposrted to another location.  How can I handle these to somehow get rid of them or do they really not do anything except clutter up the content?
Thanks

Answer 1

Now I think I understand even less than before about your workflow
So let me continue with [more questions]:
Are you using a Mac or a Windows-PC?
Msmoto1 wrote:
I move NEF files from the XQD card inot a file called NEF Dirct [via Windows Explorer or Mac Finder?], this being on a 2 TB hard drive attcahed via USB.  From this NEF Direct folder, I then import the files to LR [via ADD in the import dialog of LR?].  I further deit, deleting about 75% of the files from the disk after impart. [could have some danger here so early, so I'd be cautious and just label them as reject - hit letter X, do actual deletion sometime later.]
To make it easier to find the NEF files once I have taken them in from the XQD card [why find them - in which software? LR is sufficient, you need not consciously know where the files are as long as you do every subsequent move from within LR], I every now and then close the folder and crewate a new folder [via Windows Explorer or Mac Finder?] to bring over the NEF files from the card.  My suspician is this either changing the folder name or something in this area is why the NEF files are not seen by LR. [should not matter if you do this before the import. Afterwards you would break the link if done outside from LR.] In spite of this, the ones brought up by the aparent glitch after the backup on 12.27.12 show the actual image exported to another folder on the same external hard drive, but do not seem able to find the original NEF files. [Does that mean you have "?" in your thumbnails, saying the file is offline or missing?] [Did you do an Export from LR?]
So, while the catalog is a bit cluttered, it is not showintg the most recent images in both NEF and JPEG, so maybe it is a wait and see issue. [There are no wait and see issues. LR needs some time to create its previews, but you see the thumbnails all the time.]
I suppose I could somehow go back to the 12.27.12 backup catalog and import the more recent images form the current catalog.  Is this possible? [Did you already do some work on these more recent images, like keywording and developing?]
Generally you can merge 2 different catalogs into 1, but careful setting of check-marks, in order to not have even more clutter by virtual copies.
You would open the catalog with most good stuff in it: assume the 12.27.12-catalog, or better a copy created by Windows Explorer/Mac Finder, in order to still have it - things can always go wrong.
Then you choose Menu File-Import From Another Catalog, then select your current catalog.
LR will show a box for "preparing", then come up with a dialog box:
if there are new photos found (bound to in your case), you can add them without moving.
If there are metadata changes to the images which overlap in both catalogs, you can select from the dropdown list to Replace Nothing /  Metadata and Develop Settings only / Metadat, develop seetings and negative files.
You can tick for a virtual copy (so you have 2 interpretation versions, one from each catalog). If tick "Show preview", you get a similar list of thumbnails like in the original import dialog to Check all, Uncheck all and recheck selectively.
You could ease this if you would not take the full current catalog as source for the merge, but export from your current catalaog the supposed incremental portion of images in between Dec27 and today. Then there would be no overlap between the 12.27.12-backup and the source. You do this by first opening your current catalog, selecting the images between Dec27 and today, then go for File-Export as catalog.
All this ex-/importing of catalogs may be superfluous if you did not yet invest work in the images between Dec27 and today, other than merely importing them into your current catalog.
If so, then simply re-do the import into the 12.27.12-copy.
My instructions only work if you have all the NEFs available, and can remove any "?" by plugging your external USB-HD.
If you should still have "?" which you cannot relink, you are in more trouble.
Forgive me if I may understimate your LR knowledge due to your juniority on this forum, but it may be worth while to first ensure your overall understanding of LR. If you learn best by watching video tutorials, I'd recommend Julianne Kost's intro series http://tv.adobe.com/show/getting-started-with-adobe-photoshop-lightroom-4/.
If you prefer reading material for easy searchability, I'd recommend an eBook from Victoria Bampton: "The missing LR FAQs" http://www.lightroomqueen.com/books/adobe-lightroom-4-missing-faq/
Good luck,
Cornelia