Upgraded to iTunes 11.4 and now it won't sync my iPhone 5s-sync button is greyed out.

I believe the issues with AppleUSBEthernetHost.kext and AirTrafficHost.framework are unrelated, actually. According to what I've read, AppleUSBEthernetHost.kext is used by the Apple USB Ethernet adapter as well as by the iPhone when doing USB tethering (the iPhone shows up in the Network control panel). For more info, see:

http://blog.iphoting.com/blog/2012/09/04/fixing-broken-iphone-usb-tethering-on-o s-x/

AirTrafficHost.framework on the other hand appears to be used when syncing devices over WiFi instead of USB. This one doesn't have quite as much info, but a few links:

http://www.shouldiblockit.com/airtraffichost.dll-2846.aspx

http://triviaware.com/macprocess/id/5310

Apple fixed AirTrafficHost, so syncing should be good with 11.4 now. I think having a broken AppleUSBEthernetHost prevents the use of USB tethering. If anyone uses that, perhaps they can test?

I am having the same issue with the sync button being grayed out after I upgraded iTunes. I need my iPhone 5 to talk to my computer again. Just like others, I'm running a 2 GHz Intel Core Duo iMac with 10.6.8 Snow Leopard. This must be Apple's way of telling me to upgrade....but I still love my baby. It's been a good machine. I need some step by step instructions from some kind person on how to reinstall itunes (currently using 11.4) in order to fix this. So many questions.....how do I delete my current version of itunes, do I even have to, what happens to all of my music/playlists when I reinstall. I am scared of this venture because I'm not the computer genius that so many of you are and I don't want to loose all of my music. I literally need someone to hold my hand on this one. I hope I'm not insulting anyone's intelligence by asking for this basic help. Thank you in advance.

Try downloading iTunes 11.4 and re-installing, first, since it's easy. This may replace the bad files from the first attempt. You might try restarting after the re-install to make sure the newer files are being used.

If that doesn't work, you SHOULD be able to just remove iTunes and /System/Library/PrivateFrameworks/AirTrafficHost.framework/ and then re-install iTunes 11.4:

1) From the Finder, press shift-command-G and type /System/Library/PrivateFrameworks/ to open this hidden folder. Find AirTrafficHost.Framework and drag it to the trash.

2) Open Applications and drag iTunes to the trash.

3) Run the iTunes 11.4 installer and when finished, restart

None of these steps will touch your media, playlists, or backups.

You cannot drag iTunes to the trash. The system responds it is necessary for the OS.

Problem solved after speaking with Apple customer support all you have to do is reinstall iTunes as it's been updated it was that simple!

However, all my pages documents have now disappeared on the cloud :-/

Thank you so much elentar for helping me be brave and giving me the push I needed to try "something." The reinstall worked, it was that simple! My phone and mac are now communicating once again. No lost music files like you promised. One last quick question.....an upgrade to iOS 8.0.2 for iPhone, is it wise or are people having issues with this? Thank you again! 😍

I'm afraid I don't know if 8.0.2 is any better than 8.0.1 was, hopefully someone else can answer that. I suspect it's probably fine but it might not hurt to wait a few days anyway, since you just got everything working well.

Agreed. It's wonderful to be able to use the sync feature again. I don't need any new problems. I'm going to sit tight for awhile before doing any upgrades. Thanks. 🙂

"I think having a broken AppleUSBEthernetHost prevents the use of USB tethering. If anyone uses that, perhaps they can test?"

Wow. Fascinating stuff. Thanks for the links. I can't imagine why they would use that driver for 2 seemingly-disparate things like that?? 😕

Given that I can't seem to get the 11.4/11.4++ AppleUSBEthernetHost kext to load on my Mac Pro (see my previous post a couple of pages back), I guess all I should have to do is open the Network Control Panel and plug in my iPhone 5 to see that it doesn't work, right?

So I did - and when I plugged in the iPhone 5, nothing changed in the panel and when I went to manually add a new device, the list that popped up did not show the iPhone. Luckily I don't often have a reason to USB tether my Mac Pro ... (I only lose power a couple of times a year, on average)

After deleting these file my macbook is running super slow and my dock is gone completely... is there anywhere i can get those files to reinsert them?

I've reinstalled itunes 11.4, zero problems and zero error messages, now I can sync iPhone again 🙂

I was struck by this thread's issue and got sync working again with cwa2's info, but just got prompted to install iTunes 11.4 (18) _again_, then to install iOS 8.0.2 on my 5th gen Touch, and all is again well. I risked it since I figured I could fix it again if things went wrong. I have no idea whether or not the files I replaced were installed over or not, but I can report that my ~2005 32-bit Intel iMac and 5th gen Touch work fine now with iTunes 11.4 (18) and iOS 8.0.2. Thank you for fixing this, Apple (I _think_...maybe there's still framework holes, I dunno).

Thanks jecauril!

Pretty much what I expected, but it's good to get it confirmed by someone with a 32-bit only system.

So basically we're all in the same boat, if you are on 10.6.8 AppleUSBEthernetHost.kext is busted whether you are on a 32-bit system or a 64-bit system.

I decided to see what would happen if I went back in time with these kexts.

First I tried AppleUSBEthernetHost.kext version 2.3.6, which is from iTunes 10.7 I think. That wouldn't (kext)load, either 😟

So I went back to version 2.2.0 which I think is from iTunes 10.6.3. Finally, one that loads!!!

[20:00] nightowl:/<1>Library/Extensions % kextstat | grep AppleUSBEthernetHost

  152    0 0xffffff7f80e36000 0x5000     0x5000     com.apple.driver.AppleUSBEthernetHost (2.2.0) <38 32 5 4 3 1>

Unfortunately, after loading it I went to Network in System Preferences and plugged in my iPhone 5, but nothing happened 😟

I don't get it - the kext is now loaded, I shouldn't have to reboot to make the Network panel see the device if the kext is loaded and working, right?

I have two old entries in Network; "iPhone" (Not Connected) and "iPhoneModem" (Inactive). Neither one changed when I plugged in the iPhone.

Is there a chance this isn't working because I don't have Personal Hotspot enabled/set up? (I don't think AT&T will allow me to set it up on my grandfathered "Unlimited" data plan.)

(Yes, I realize at this point I'm veering dangerously close to being off-topic.)

I found that I set my restrictions to not allow Installing Apps, Deleting Apps, In-App Purchases when setting up IOS8.

Settings>General>Restrictions

Turned them back on, apps synced no problem!