I am a long time PC user and have recently switched over to the Mac side. I have found that getting answers to questions regarding system level issues can be quite a challenge so I decided to post something specific here in hopes of getting a specific kind of answer. I travel extensively so I rely heavily on compact external hard drives to manage my data needs. Since I do Photography and Video this means I tend to have 3 or 4 drives working all the time. The issue I need help with I originally discovered using Aperture. Whenever I shut down my system and moved it Aperture would have issues finding all of my photo files when the system was restarted. This resulted in a rather laborious task of pointing out to the application where the files were manually before I could get back to work. No good answers on the Aperture forums on how to keep this from happening. I have since discovered this is also an issue with Itunes and probably most of the applications that use a library files to keep track of file locations. It does not seem to matter if the drive is formatted FAT or Mac, nor does it matter if I have 1 or more than one drive plugged into the laptop. Shutting down and restarting the system seems to be all that is required for any Mac application to completely lose track of its files even if nothing has been touched as far as hardware is concerned. I have a Drive for Music and downloaded Itunes content, another for photos and yet another for video. They are not always attached when I am say checking email but they are always mounted before I open any application that needs the files contained on them. This was never an issue on the PC side. Can someone explain to me how OS X keeps track of this info and what I need to do so that I do not have to hunt down all of my files manually everytime I want to use an application? Yes I did move my Itunes files in the recommended fashion. It worked perfectly right up to the point I shut my machine down and restarted. Same goes for Aperture. Any pointers would be most welcome. I am posting this here because it seems to be a systemwide issue not just with the applications I have noticed this behaviour affecting.