These directions apply toiTunes12 and up but should work equally well for earlier versions, too.
The instructions in this article also apply to deauthorizing computers in the Music app.
sign on with your Apple Account if prompted to do so, then clickDeauthorize.
Or maybe you want to deauthorize iTunes or Music on a non-working computer that won’t turn on.
Go toAccount>View My Account.
access with your Apple Account.
In theApple Account Summarysection, selectDeauthorize All.
In the pop-up window, confirm that this is what you want to do.
In a few seconds, all the computers on your account will be deauthorized.
So, you’ll have toreauthorize the ones you want to use.
EveryApple Accountcan authorize up to five computers to play the DRM-protected content purchased using that account.
This number limit applies toMacsand PCs, but not toiOSdevices like theiPhone.
