Authorize a Mac to play purchases
To play certain purchases, you must authorize your computer using your Apple ID and password. (Authorization helps protect the copyrights of some purchased items.)
You can authorize or deauthorize a computer at any time.
Authorize a computer to play purchases
You can authorize up to five computers (Mac, PC, or both) at a time. To play a purchased item on a sixth computer, you need to deauthorize another one. An iPhone, iPad, iPod, or Apple TV device doesn’t count as a computer.
In the Apple TV app on your Mac, choose Account > Authorizations > Authorize This Computer.
If requested, enter your Apple ID password to confirm.
Deauthorize a single computer
Be sure to deauthorize a computer before you sell it or give it away. This prevents it from continuing to count as one of your authorized computers and from playing your purchases.
In the Apple TV app on your Mac, choose Account > Authorizations > Deauthorize This Computer.
Deauthorize all authorized computers
If you forgot to deauthorize a computer you no longer own, and you’ve already authorized five computers, you can deauthorize all your computers at once. You can use this method once a year.
In the Apple TV app on your Mac, choose Account > View My Account.
On the right, click Deauthorize All.
If you don’t see this option, you have fewer than five authorized computers.
If you have trouble deauthorizing a computer, see the Apple Support article Authorize or deauthorize your computer for iTunes Store purchases.