Why did the # of images in my catalog double when I 'Moved' them in LR from one ext. drive to a 2nd?


Why did the # of images in my catalog double when I 'Moved' them in LR from one ext. drive to a 2nd?
I'm running LR 3.4 64bit on a PC. My external drive starting generating error messages so I went out a purchased a 2nd external drive (3TB Seagate)  to migrate my image Catalog over.  Within LR's Import dialog screen I selected the Source drive (old; error-generating drive) and the Destination as my new drive. I ensured that Move was selected (vs. Copy or New).
I had on the order of 50k images. This morning I checked my catalog and the files appear to have moved over just fine. However, now the image count is >100k!
Any ideas on 1) what I did wrong, 2) what steps I can take to 'de-duplicate' the images in my catalog without manually going through?
Thanks in advance!
I notice it that users often use the Import feature in LR incorrectly. That creates a lot of problems.
The Import feature is for images that are NOT yet in LR. Only when - for some reasons - you want the same images twice in LR you use the Import and un-check the "Do not import suspected duplicates".
In your case you must have un-checked the "Do not import suspected duplicates" -box in the Import dialog.
As the previous poster already noted the best way to move whole folders or even drives of images is to move them in your OS.
In LR you then get a question mark besides the folder where the photos previously were.
Just right-click the folder with the question mark and point LR to the new location - that's all.
But you imported and now all images show twice.
If your images are all on the new HD (check if they are all there!), right-click the top-most image folder on your "old" HD and select "Remove". This will remove the folder from LR but will not delete your images. LR should then show only 1 set of images on your new HD.
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