The files are stored on a firewired external hard drive but all appears to be the same. iTunes recognises the tracks on the external hard drive and would search if it was unable to identify immediately (as it does if I download a track from LW which I can then see in iTunes. If I move the file to the external hard drive to be with the rest then iTunes tells me it can't find the file and asks if I wish it to search. I do, it does and all is OK). What if I put a thousand files on the hard drive, add the source to LW and see if these are hashed just the once? I'm not keen to mess about with the iTunes files so I could just copy a load and delete later. I noticed that when I deleted LW and installed the latest version over the weekend all my preferences were retained so maybe I hadn't unistalled correctly. For the Mac I highlight the programme and move to trash. Is there a better way to remove LW completely for the Mac?
It must be very difficult to do your job when so much of it is blind and dependent upon the knowledge of someone else!