How to sync an iPhone with iTunes 12?

Do you sync over wifi or by plugging it into the MacBook?

OK. So when you plug it in, what happens?

When I plug in my iPhone, along the top row of icons, a new one appears in the shape of a phone. If I click on that, I get a sidebar with info on my phone and to the right is information similar to what I'd see in previous versions of iTunes. I have it set up to sync when connected, so the sync starts immediately.

(Edit...)

Here's the icon that I get when I plug the phone in:

I also don't see the phone icon appear when plugged in.

My iPhone is charging and I can download images using aperture but iTunes won't recognise it...

iPhone 4s, running iOS 7.1.2

iPhone 4s, running iOS 7.1.2

What OS X version on the Mac?

The OP is using Mountain Lion.

I'm on Mavericks (holding off on Yosemite until the feedback gets better) and I'm able to sync iPhones running 8.0.2 and 7.1.2 and also an old iPod Touch running 5.1.1.

OS 10.10 (Yosemite)

Hmmm. Well, I'm not going to guess that it only works with Mavericks, but that is curious.

Taking a stab in the dark here: If you go to iTunes -> Preferences and click on the Devices tab, what do you see there?

For me, I see all of my devices and the last sync time. The box that says "Prevent iPods, iPhones, and iPads from syncing automatically" is not checked.

No icon, can't sync device... this is totally out of control.

Had similar issues with iTunes 12...no device icon via wifi or when devices are tethered. Running Mavericks with 6 devices (5 on 7.1.2; 1 on 8.0.2). iTunes very slow to launch (up to 45 seconds). When tethered; the 7.1.2 devices (only) would kick off iPhoto for downloads; the 8.0.2 device would not. Further; when tethered all devices would ask to "Trust Computer"...repeatedly.

Performed numerous restarts on devices and iMac, turned wifi off/on (all devices), reset network (all devices), and deauthorizing/authorizing iMac in iTunes...nothing helped.

What worked for me: iTunesHelper seems to be my culprit. Go to System Preferences > Users & Groups > Login Items and checked off iTunesHelper. Restarted the machine. All back to working order (save for wifi sync on 8.0.2 device...which is another kettle of fish).

What worked for me: iTunesHelper seems to be my culprit. Go to System Preferences > Users & Groups > Login Items and checked off iTunesHelper. Restarted the machine. All back to working order (save for wifi sync on 8.0.2 device...which is another kettle of fish).

This reminds me... When I was performing the iTunes update, I got caught in a Catch-22. The installer said it could not continue until I quit iTunes and iTunes said I couldn't quit because the installer was running. I found a tip that said to go into Activity Monitor and kill any process that contained "iTunes" in the title. Once I did that, the installation went smoothly. So I do wonder if another process like the Helper is creating problems.

The only other thing I can think of at this point is that the trust relationship is messed up. See this article(particularly step #1) and then make sure the device is unlocked when you connect it to the Mac. Check to see if it is asking if the computer should be trusted.

Other than that, I'm out of ideas for now.

I have been having the same problem with my iPhone not syncing to iTunes. I sync mine also with USB and what I found out was you have to unlock your phone and plug in the cable while iTunes is open. After you do this you should be asked if you want iTunes to use your information from your phone and a message that says something like " do you want this computer to be trusted" or something like that and just click trust and thats how mine successfully synced with iTunes. I hope this helped in some way 😀 i also run this on an iMac with the new update.

after you have went through that process restart your computer and your device and it should work