Recently I got a iPhone 5 with iOS 9.3 installed. On connecting it to my computer iTunes said that I needed at least iTunes 12.2.2. I had 12.0 at the time. Mac Running Yosemite.
I clicked download, and App Store launched, and said I had no updates available.
Went through this loop several times.
Called Apple.
Spent an hour on the phone, while the very personable agent walked me through the direct link (support.apple.com/kb/dl1814) Clicking the download button there got me to another page. Clicking download there got me a "Thanks you for downloading…" but the download didn't begin.
I repeated this step with chrome, firefox and safari. No joy.
Booted into safe mode. Didn't help.
Went to two other computers, my wife's where I don't have a login, and my laptop, which runs snow leopard.r No joy from either of those.
We left the ticket unresolved.
Best Answer
Since the apple advisor was able to perform the download at his end, but I was not able to at my end, my suspicion was that there was a problem with Apple's content distribution network.
This morning I tried again. No joy.
On a hunch I tried logging in on a spare admin account. No problem. connected to the apple support site, and downloaded the update. Worked like a charm.
At this point it's not clear what happened, but with odd behaviour it does bring up one additional possibility to try:
Attempt the update as a different user.