How can I "authorize" a computer?

Question

I'm trying to sync my iPhone to my MacBook Pro. I connect the iPhone, launch iTunes, click on the device, then click "Sync".

1

I'm presented with this dialog:

2

I click "Authorize". Then I get this dialog:

3

I fill in the information and click "Authorize".

Then I get this dialog:

4

I click "OK" and instantly I am presented with the first dialog above, the one that says, "This computer is no longer authorized..."

Then it just enlessly cycles between those three dialogs, never letting me authorize the computer.

Any ideas?

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Mac OS 10.7.3

iTunes 10.6.1 (7)

Answer 1

There is an Apple support article that gives a couple solutions here:

http://support.apple.com/kb/TS1389

I've also seen people with this problem solve it by downloading and re-installing iTunes manually from here:

http://www.apple.com/itunes/download/

I would try the 3 suggestions in the Apple article first (because they are easier) and then try the download and install.

Answer 2

I suggest de-authorising the machine before connecting your phone, then authorising the machine again.

Use the Store menu in iTunes to Deauthorised the computer.

Authorisation is linked to the hardware UDID, so it's possible that the machine was registered before a clean OS X install for example.