Data Lost.....

Telling us what you did when you moved the music would be helpful in identifying exactly what might have resulted in this data loss.

 

Lost or just missing? I moved my library to another drive and had a ton of them with broken links. I finally wrote down my playlists, started a new library and dragged the new library back into iTunes. Sure I lost counts and stuff, but all my music was there, so no big loss.

 

I suspect that iTunes is just confused, and doesn't know where all your music is. Correcting this is quite simple - find the iTunes Music folder on your external drive and tell iTunes to add its contents to its library. iTunes will sort through the folder and add anything that isn't already there.

 

Weird? Permissions issue with copy-over? I've had cases where file appeared to be missing when viewing them over the network on our server, but could see them when sitting at the server. Came down to repairing permissions fixed it. Were the missing songs originally tied to another user account before having them on the network drive? Hopefully you have the missing music on an iPod?

 

Can't you move your music folder to another drive and then in iTunes preferences change the location of your music folder under Advanced>General>iTunes Music Folder Location ... That's how I would do it.