How to Authorize Computers in iTunes

Authorizing a PC or Mac in iTunes grants your computer permission to play media content purchased through the iTunes store and protected by DRM (digital rights management) technology. Under Apple's licensing system, you can authorize up to five computers on an iTunes account for this purpose.

Media content can include movies, TV shows, audiobooks, ebooks, applications, and movies. If you want to use some kinds of media purchased from the iTunes Store, you need to authorize your computer to play them (with the removal of DRM from music bought at the iTunes Store, it's no longer necessary to authorize computers to play music from iTunes).

The computer you buy the media on from iTunes is the first computer of your total five that is authorized to play it.

Here's how to authorize other computers to play your iTunes purchases.

1. Add the file you want to use to the new computer. Options for moving files from one computer to another include:
   1. • Home Sharing
2. Transferring purchases from iPod/iPhone
3. iPod copy programs
4. External hard drive
5. Once you've dragged the file into the second iTunes library, double-click it to play. Before playing the file, an iTunes prompt will pop up asking you to authorize the computer.
6. At this point, you need to log into the iTunes account using the Apple ID under which the media file was originally purchased. Note that this is not the iTunes account associated with the computer you're on and to which you are currently adding the media file (unless you are transferring your media files to a new computer that replaces the old one that you have deauthorized.)
7. If the entered iTunes account information is correct, the file will be authorized and will play. If not, you'll be asked again to log in to the Apple ID used to buy the file. Note that if the iTunes account used to purchase the media has reached its maximum of five authorized computers, the authorization attempt will fail. To resolve this, you will need to deauthorize one of the other computers that are currently associated with the file's Apple ID.

Alternatively, you can authorize a computer ahead of time by going to the Account menu in iTunes. Hover over Authorizations and select Authorize This Computer... from the slide-out menu.

NOTE: iTunes allows only one Apple ID to be associated with iTunes at a time. If you authorize a file with an Apple ID other than the one currently associated with your iTunes purchased media library, you won't be able to play those purchases until you log back in under that Apple ID (which consequently will cause the new items that were purchased under the other Apple ID not to work). 

Since you only get five activations, you may from time to time want to free up one of your activations or prevent playback of your files on another computer. To do this, in iTunes go to the Account menu and then to Authorizations, and choose Deauthorize This Computer... from the slide-out menu.

As of January 2009, all music at the iTunes Store is DRM-free iTunes content, which removes the need to authorize computers when playing songs.​

If you no longer have access to a computer that you previously authorized on your Apple ID (because it is dead or nonfunctioning, for example), and it is taking up one of the five authorization slots that you now need for a new computer, you can deauthorize all computers under that Apple ID, freeing up all five of those slots so you may reauthorize your computers.