Authorise a Mac to play purchases
To play certain purchases, you must authorise your computer using your Apple ID and password. (authorisation helps protect the copyrights of some purchased items).
You can authorise or de-authorise a computer at any time.
Authorise a computer to play purchases
You can authorise up to five computers (Mac, PC or both) at a time. To play a purchased item on a sixth computer, you need to de-authorise 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 > Authorisations > Authorise This Computer.If requested, enter your Apple ID password to confirm.
De-authorise a single computer
Make sure you de-authorise a computer before you sell it or give it away. This prevents it from continuing to count as one of your authorised computers and from playing your purchases.
In the Apple TV app
on your Mac, choose Account > Authorisations > De-Authorise This Computer.
De-authorise all authorised computers
If you forgot to de-authorise a computer you no longer own, and you’ve already authorised five computers, you can de-authorise all your computers at once. You can use this method once a year.
In the Apple TV app
on your Mac, choose Account > Account Settings.On the right, click De-authorise All.
If you don’t see this option, you have fewer than five authorised computers.
Scroll down and click Done.
If you have trouble de-authorising a computer, see the Apple Support article Authorise or de-authorise your computer for iTunes Store purchases.