I did this om my PC. But when I opened it for the first time again I opened it from the Lightroom base file in the windows file manager. Next time it was no problem. (did this with 3 d-bases)
Since you are talking about moving files, perhaps someone can point me in the right direction. I'm on a PC--my 2007 files are all on a dedicated (but not external) drive--and I will empty that drive, probably reformat, and reference the LR files all from the external. Dumb me---I should have referenced the files originally from the external (archive), but I didn't. So--now when I will have them only there--how will I handle this? Right now 4+ years are referenced from various externals, but the 2007 files are not. When I would move files on Imatch, I was able to designate that I was moving them, then it would allow me to name the DVD, drive, etc. and show that they had been moved.
I can't see anything on any of the menus that will allow me to do this---and they are all keyworded. Otherwise, it would seem the easiest to delete and reimport/reference on the new drive. I suspect I am missing something here. Though I am not ready to do this, I need to figure out how--and I should probably reference all the rest of 2007 from the external (as I copy to it immediately). I just looked at the Lightroom Adventure book (the only LR reference I have) and find nothing there either. Hope someone can set me straight.
BTW--part of this confusion probably lies from the fact that I've just started to use LR again. I had and used the beta, but when PSCS3 came out I had decided to stick with my normal workflow (except for switching RCs to ACR4.1. After watching the C2P videos I decided I may be missing something (one of the things was being able to reference to externals and still view the thumbs in the library) and watched the LR tute videos. So---I cleaned out my 'beta' library, installed 1.1 and imported all my images (well up to 5+ years ago). I just screwed up on referencing the 2007--so now I'm at a loss as to what to do--after keywording the whole year LOL.