First things first, don't trash your library file. This file holds all your song data, ratings, and houses the structure to re-build your entire library for you, dependant on the original source of the imported songs, being available.
How do I display duplicated songs in my iTunes library?
In iTunes, goto View > Show Duplicates.
How do I delete these duplicates?
Two ways.
One - Go through each duplicate song individually and choose to delete it from the library and delete the origin file.
Two - Use Ctl/Cmd commands to select multiple song duplicates and choose to delete them from your library and delete or remove the origin file.
After you have resolved and trashed the current duplicate files from your library, click 'Show all Songs' to return to your non-duplicate-display of your library.
You are now ready to import from your external HD.
In iTunes goto File >Import > (Find the folder you wish to import) > Ok
This is the important part. Regarding deletion of songs after import on your external. iTunes needs a file structure to be in place at all times, to read music, this consists of
iTunes > iTunes Music
As default, iTunes manages your music in:
My Music > iTunes > iTunes Music
... and this is where your iTunes library xml file should be situated.
As long as you keep this file structure, and the iTunes library file in place, iTunes will find you library. So if you intend to run your library from your internal HD, instead of the external, if this directory doesn't exist you must create it. Then you can tell iTunes where the new structure is by going to:
On Windows:
In iTunes > Edit > Preferences > Advanced Tab > iTunes Music Folder Location > Browse > (Find the new location of the directory structure which houses your iTunes music folder)
On Mac:
In iTunes > Choose iTunes on the menu bar > Preferences > Advanced Tab > iTunes Music Folder Location > Browse > (Find the new location of the directory structure which houses your iTunes music folder).
I hope some of this was helpful to you.
R-Fly
