okay, let me rephrase my question:
when you
moved your files from the old Mac to the external, did you
(a) drag the
entire iTunes folder from <MacintoshHD>/users/<yourname>/music to the external
or
(b) use the +consolidate files+ command to move the files to the external
if (a), connect the external to the new Mac and launch iTunes while pressing
option on your keyboard. when prompted, click on +choose library+ and select the iTunes folder on the external.
if (b), copy the iTunes folder from <MacintoshHD>/users/<yourname>/music on the old Mac to <MacintoshHD>/users/<yourname>/music on the new one, overwriting the iTunes folder in place there. connect the external to your new Mac and fire up iTunes normally.
if you want to move the media files from the external to the internal disk of your new Mac, go iTunes > preferences > advanced and point +iTunes media folder location+ to the iTunes folder in <MacintoshHD>/users/<yourname>/music. also on the
advanced tab, make sure there is a tick in the boxes next to +keep iTunes media folder organized+ and +copy files to ... when adding to library+.
then file > library > organize library > consolidate files. this will copy all your media files to the location you specified earlier in the
advanced tab. when done, you can (if you want) erase the external and use it for other purposes. or keep the files there and use the external as your backup.
J
GG