You May Have Only Deauthorize all computers once per year.You must wait until Agust 5 .. Plz Any Help Here ??

That is how it works. You can deauthorize indivdual computers that you have access to free up space for a new computer that you want to authorize. If you really need to reuse the feature before the time limit expires you can ask at https://www.apple.com/support/itunes/contact/. They may be able to grant a one-time exception. In future deauthorize unneeded instances of iTunes as and when you stop using them.

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