Q: I’ve recently bought a new computer and went to authorize it for my iTunes Store account only to discover that I’ve reached my maximum 5 out of 5 authorized computers. I think I can account for 3 of those, but have absolutely no idea where the other 2 have come from. Is there any way of finding out where those computers are and de-authorizing them?
A: There isn’t any way to get a list of which computers have been authorized previously, but chances are that those other two computers no longer exist as far as iTunes is concerned. If you’ve ever reinstalled your operating system or performed a major hardware upgrade such as changing the motherboard/logic board on one of your authorized computers, iTunes would in fact have considered your existing computer to actually be a different machine and therefore require a separate authorization, using up one of your additional authorization slots. For this reason, it’s always a good idea to de-authorize your computer from within iTunes before you reinstall the operating system or perform any major hardware upgrades.
The good news, however, is that Apple does provide iTunes Store customers with a way to reset all of their authorizations once they’ve reached their five-computer limit. You can check the number of computers you have authorized simply by logging in to your iTunes Store account from within iTunes—simply click your account name in the top-right corner of the iTunes Store window and then enter your iTunes Store username and password when prompted. Immediately below your account and billing information, you should see a “Computer Authorizations” section which indicates how many computers you have authorized for the current iTunes Store account. If you have all five authorizations used, you’ll also see a “Deauthorize All” button appear to the right of this section.
Clicking on the Deauthorize All button will reset your authorization count to zero. You will then need to revisit each of the computers that you actually want authorized and re-authorize them by choosing Authorize Computer from the Store menu in iTunes.
Note that Apple only allows you to deauthorize all of your computers in this manner once every 365 days, so this method should not be considered a substitute for properly deauthorizing your computers manually.