Hal . . . I believe I may have experienced the same problem you describe when I have attempted to select a number of picture files by highlighting a large group of pictures on my Windows XP computer. It seems there is a limit as to how many pictures to
"grab" at one time. If I highlight too many pictures, Windows XP starts to make duplicates, i.e. picture #1 and picture #1_1, etc.
I don't know what the magic number is that Windows XP starts to make duplicates, but I always have to methodically delete the duplicates and start over by selecting a smaller number of pictures to move
Dan