Dave Oddie: I find the 'Don't Import Suspected Duplicates' option to be rather useless because I rename my files on import and LR doesn't remember that when you imported DSC0001.ARW you renamed it to "Oulton Park 20120710 0001.ARW" or whatever.
Unless of course I am missing some setting or other to get this to work!
As LR is a database driven program storing the original file name when doing a rename doesn't seem unreasonable to me.
Strangely enough, LR does remember it! I rename on import but then again when LR is shown the same memory card with the first batch of photos still on it, it somehow recognises them...
Valentin Hertz: Apparently make a second copy to, it's not supposed to rename your files. Wrong, regardless what I tried those files always get renamed also. I wanted to use this option to copy all files from cameras to a second hdd before LR touches. That's not possible.
Please help me if you know how to do it, other than copying it manually.
It depends what you use: I work with Super Duper to keep my HDs in synch, so no need to create a separate backup. At the same time I won't erase a card until I'm sure both HD versions are stable