​How to move your iTunes library to a new computer

When you get a new computer, you can move your iTunes library so that you can play your media on and sync with your new computer.
Before you begin, make sure you have a new  backup iTunes library or update your existing backup before you move it. Even if you already have a backup iTunes library existing, this step makes sure you capture any changes and makes the process easier. You could even move iTunes library to a new computer to make things easier.

Migration
If you want to move iTunes library to a new computer or Mac, you can migrate your data from another Mac or a PC. If you are replacing your PC, you might be able to use Windows Easy Transfer. This option might be slower than other options, but it’s more thorough. Use an external drive and this makes it easy to move library to a new Mac  even if you have a back up ITunes library.

How to move library to new  PC

If you’re using this method on a Mac:
From the Finder menu, choose Preferences.
Make sure that the boxes next to “External disks” and “Hard disks” are enabled.

Part 1: Install iTunes
Download and instal  ITunes of the latest version.

Part 2: Move any new content
If you’ve used iTunes on your new computer, move your media to a new folder. This will keep anything you added to your new computer separate from your old library. These files can be added back to your library in.

 Part 3.

Move your folder (Mac)
Move your folder (Windows)

Part 4: Copy the  backup from your old computer
To copy all of your media files, including the library file that holds all your playlists and other settings, to your new computer:

Open iTunes.
You’ve now moved all of your music, playlists, and other information—including play counts and ratings—from your old computer to your new one.

Part 4 (optional): Add back new content
Copy the ITunes Media folder you created in Part 2 into the “Automatically Add to iTunes” folder inside the iTunes Media folder you copied in Part 3,it will automatically import the content and can then be used in the cloud.

If you don’t have a backup of your  library and your old computer is unavailable, you can download past purchases made with your Apple ID through iTunes in the Cloud.

If you have multiple Apple IDs, you might find it easier to transfer purchases from a device after authorizing your new computer with your Apple ID.

If you previously subscribed to iTunes Match, you can turn on iTunes Match once your new computer is authorized.

After you transfer your library

If you plan to stop using your old computer, deauthorize it by choosing Store > Deauthorize This Computer from the menu bar.
If you used it on your old computer to back up your iOS device, back up your devices on your new computer or manually transfer the backups from your old computer. Learn more about creating and deleting iPhone, iPad, or iPod touch backups in iTunes.

If you used iCloud with your old computer for syncing, set up iCloud on your new computer.
If you will continue to use your old computer, recreate your library. This prevents an iOS device from seeing the old computer as the new one because of the old library files and does not create troubles with the iOS device.