iTunes Store purchases can be authorized in iTunes to play on up to five computers. Deauthorizing a computer allows you to manage which computers can play purchased music, videos, audiobooks, or other content.
Authorization helps protect the copyrights on the content you buy. You can use your digital rights management (DRM) protected music purchases1 from the iTunes Store on up to five different computers (this can be any mix of Macintosh or Windows-compatible computers). When you play an item you've purchased, your computer is "authorized" to play content purchased using your Apple Account.
Note: Songs you encode in AAC format from a source other than the iTunes Store, such as your own audio CDs, do not need to be authorized.
To authorize a computer to play purchases using your Apple Account
Select a song, video, or audiobook you've purchased (in your library or the Purchased playlist).
Click the Play button.
If the computer is already authorized, the item plays. If the computer has not yet been authorized, iTunes asks you to enter the Apple ID and password you used to purchase the song.
Remember to deauthorize your computer before you sell it, give it away, or get your computer serviced.
To deauthorize a computer
Open iTunes.
From the Store menu, choose Deauthorize Computer (In earlier versions of iTunes access this from the Advanced menu).
Select "Deauthorize Computer for Apple Account" and enter your Apple ID and password.
Make sure you deauthorize your computer before you upgrade your RAM, hard disk or other system components, or reinstall Windows. If you do not deauthorize your computer before you upgrade these components, one computer may use multiple authorizations. If you find you have reached 5 authorizations due to system upgrades, you can reset your authorization count by clicking Deauthorize All in the Account Information screen. Note: You may only use this feature once per year. The Deauthorize All button will not appear if you have fewer than 5 authorized computers or if you have used this option within the last 12 months.
To deauthorize all computers associated with your account
Click iTunes Store in the Source pane.
If you're not signed in to the store, click the Account button, then enter your account name and password.
Click the Account button again (your ID appears on the button), enter your password, and then click View Account.
In the Account Information window, click Deauthorize All
