Authorise a computer to play iTunes purchases
To play many purchases from the iTunes Store, you must authorise your computer using your Apple ID and password. (Authorisation helps protect the copyrights of the purchased items.)
You can authorise or deauthorise a computer anytime.
Authorise a computer to play iTunes Store purchases
You can authorise up to five computers (Mac, Windows or both) at a time. To play a purchased item on a sixth computer, you need to de-authorise another one. An iPod, iPhone, iPad or Apple TV doesn’t count as a computer.
In the iTunes app
on your Mac, choose Account > Authorisations > Authorise this Computer.If requested, enter your Apple ID password to confirm.
Deauthorise a single computer
Be sure to de-authorise a computer before you sell it or give it away.
In the iTunes app
on your Mac, choose Account > Authorisations.Do one of the following:
Unauthorise a computer: Choose Deauthorise this Computer.
Unauthorise a computer to play spoken programs purchased from the Audible website: Choose Deauthorise Audible Account.
Deauthorise all authorised computers
If you forgot to deauthorise a computer you no longer own and you have five authorised computers, you can deauthorise all your authorised computers at once. You can use this method once a year.
In the iTunes app
on your Mac, choose Account > View My Account.On the right, click Deauthorise All. If you don’t see this option, it’s because you have fewer than five authorised computers.
You can also authorise up to three computers to play items purchased from the Audible website (audible.com). Audible is a third-party company that sells audiobooks and other spoken programs.
If you have trouble de-authorising a computer, see the Apple Support article Authorise your computer in iTunes.