Many programs will build a database file for the MP3s. So if you had Daft Punk’s “Get Lucky” in a “disco house folder, then it would mark it as:
[INDENT=1]C:UsersDJcRaveMusicDisco HouseDaft_Punk-Get_Lucky.mp3[/INDENT]
Now you move it all to your little hard drive, and the new path is actually:
[INDENT=1]D:Disco HouseDaft_Punk-Get_Lucky.mp3[/INDENT]
But the database file still says it’s:
[INDENT=1]C:UsersDJcRaveMusicDisco HouseDaft_Punk-Get_Lucky.mp3[/INDENT]
Thus you get problems or “file not found”.
I remember on old versions of Traktor and Deckadance I would have this problem. I see it still when I use iTunes to manage my library (because it remembers file path). Torq would make a .tqd file to sit in the same folder as the mp3, so the program would not get confused. Traktor now stores all the cue info now on the mp3, which is very cool.
Like I said, ideal solution is to scan the drive you will plug into the CDJ or what not. It should work perfectly.