...When I upgraded my internal hard drive, I copied my library over to the c: drive. In i-tunes (version 8), I went Edit => Preferences => Advanced and changed the "itunes music folder location" to the new path pointing to c:/my music. Now itunes can't find any songs -- unless my external drive is connected, so it's obviously not "getting it" that the songs have been moved.
Changing this setting would have changed the location that iTunes uses when it creates a file, e.g. downloads, rips, imports if you have copy on import selected etc. It does not update the location of exisitng files in the library unless certain conditions are met.
Normally the library files are held in an iTunes folder which is inside your profile's Music folder. iTunes creates another folder called iTunes Music (pre-Tunes 9) or iTunes Media in which to store your content. If all your content is inside this media folder then you can move the main iTunes folder to a new path or drive at will and iTunes will update the references to the files. Content that is outside of the iTunes Music or iTunes Media folder will be assumed to have stayed put. The same happens if you've relocated the media folder so that it is no longer a subfolder of the one containing the library database.
Let's assume that your music folder on your external drive is called *X:\My Music* and that your existing library files are at *C:\Documents & Settings\<User>\My Documents\My Music\iTunes*. The first step to repairing things is to use Windows Explorer to copy these library files (
iTunes Extras.itdb, iTunes Genius.itdb, iTunes Library.itl, iTunes Library.xml, sentinel & the *Album Artwork* folder) to the parent folder of that which holds your media on the external drive, e.g.
X:\ if I've assumed correctly.
Next, click on the iTunes icon in your Start Menu and *immediately press & hold the SHIFT key* until a dialog appears asking you to choose a library. Browse to X:\ and open the iTunes Library.itl file there. Open preferences, advanced and change the location of the iTunes Media folder to X:\My Music (or whatever the true value is). Click OK. iTunes should process the library updating it's links. When it's complete check that your media plays. Close iTunes and wait for it to finish saving the libray.
Now copy the library files (
iTunes Extras.itdb, iTunes Genius.itdb, iTunes Library.itl, iTunes Library.xml, sentinel & the *Album Artwork* folder) from X:\ to C:\ - don't copy the My Music folder since you've already done that. Use shift-open iTunes to open the library file at C:\iTunes Library.itl, then change the media folder location to C:\My Music again. iTunes should once again process the library and when complete you should be able to turn off your external drive and still have access to all your content.
While this works iTunes will give itself the window title of C:\, being the name of the folder in which the iTunes Library.itl file lives. You can choose to leave the music just where it is, copy the library files to the original location - C:\Documents and Settings\<user>\My Documents\My Music\iTunes - and shift-open the library there, or create a folder called C:\iTunes and move the library files & content folder into it, then shift-open once more.
You may also need to repair links to any iPod Games/Mobile Applications that were not inside the media folder before you started.
tt2