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

@airmoe, thanks for identifying that an updated 11.4 installer has been put in place at http://www.apple.com/itunes/download/ which resolves the issue with iOS devices not syncing or backing up on 11.4 on 32-bit 10.6.8 machines.

The original installer (dated 2014-09-09 05:52:52 -0700) had the problem, while the most recent 11.4 installer (dated 2014-09-23 14:24:58 -0700) has fixed the issue. Thanks to @Greg Earle for documenting which components are different in the new version of the installer.

(I verified this in my own case by syncing with my downgraded-to-11.3.1 system, as discussed earlier in the thread. I then upgraded to the known-incompatible "Sept 9" version of the 11.4 installer and verified it still had the problem. I upgraded directly from the broken configuration to the "Sept 23" version of the 11.4 installer and sync+backup are back - along with, presumably, iPhones 6 support.)

@Ksanti, I vote that you flag airmoe's post as the answer to your question and mark the discussion answered with the 11.4 re-release.

I Just went to the Apple site and re downloaded, no trashing of previous files. I can't believe it worked but 'normal service has been resumed' :-)

I've got a question for you, Jack: the Russians treat you well...? :-)

Haha, brilliant.... They're not the nicest of hosts, but they were friendlier than the Chinese....

2 gb ram to 250 gb RAM upgrade? I thought 2 was the limit. I did take mine apart and upgraded the hard drive size to 320 GB but I didn't think you could do much with the RAM.

"@airmoe, thanks for identifying that an updated 11.4 installer has been put in place at http://www.apple.com/itunes/download/which resolves the issue with iOS devices not syncing or backing up on 11.4 on 32-bit 10.6.8 machines.

The original installer (dated 2014-09-09 05:52:52 -0700) had the problem, while the most recent 11.4 installer (dated 2014-09-23 14:24:58 -0700) has fixed the issue. Thanks to @Greg Earle for documenting which components are different in the new version of the installer."

Wait, hold on, hold on - how can this be happening?

A couple of you with 32-bit machines are saying the newer installer (let's call it "iTunes 11.4++") fixed your problems.

Yet a couple of pages back, I proved that the version of AppleUSBEthernetHost.kext is completely unchanged - it's still a 64-bit only kext.

How can something not still be broken, given this fact?

If any of you out there have a 32-bit only machine running 10.6.8, and you installed the newer Sept. 23rd "iTunes 11.4++" version from the downloaded .dmg, and you are not afraid of Terminal.app, could you please open it up and run these 3 shell commands for me?

ls -lF "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost"

ls -lcF "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost"

file "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost"

Here's what the output should look like, but keep in mind I am still running on a 64-bit Mac Pro with the 'older' original iTunes 11.4 .dmg installation, not the 'new' "iTunes 11.4++" version so your output will be slightly different:

[14:50] nightowl:/ % ls -lF "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost"

-rwxr-xr-x  1 root  wheel  63024 Jul 29 13:48 /System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost*

[14:50] nightowl:/ % ls -lcF "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost"

-rwxr-xr-x  1 root  wheel  63024 Sep 10 12:07 /System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost*

[14:50] nightowl:/ % file "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost"

/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthernetHost: Mach-O 64-bit x86_64 kext bundle

iTunes 11.3.1 also includes a broken AppleUSBEthernetHost.kext. It's not broken because it's 64-bit, but because of this error:

(kernel) kxld[com.apple.macos.driver.AppleUSBEthernetHost]: The super class vtable '__ZTV20IOEthernetController' for vtable '__ZTV20AppleUSBEthernetHost' is out of date. Make sure your kext has been built against the correct headers.

The AirTrafficHost framework from iTunes 11.3.1 works fine, and so syncing also worked. My theory is that AirTrafficHost was updated in 11.4 to require AppleUSBEthernetHost whereas in 11.3.1 and earlier, it was either optional or able to work around the problem.

The updated 11.4 bundle appears to restore the situation from 11.3.1, in which syncing works but AppleUSBEthernetHost still doesn't load properly. Whether this will cause issues in the future remains to be seen. I myself an staying on 11.4 + AirTrafficHost from 11.3.1 + AppleUSBEthernetHost from 11.2.

"The AirTrafficHost framework from iTunes 11.3.1 works fine, and so syncing also worked. My theory is that AirTrafficHost was updated in 11.4 to require AppleUSBEthernetHost whereas in 11.3.1 and earlier, it was either optional or able to work around the problem."

If you go back to my (overly-long) analysis of the new version, AirTrafficHost was definitely updated in the newer version - whether it requires AppleUSBEthernetHost is another story 🙂

"The updated 11.4 bundle appears to restore the situation from 11.3.1, in which syncing works but AppleUSBEthernetHost still doesn't load properly."

If that's the case, I would think that anyone re-installing from the "iTunes 11.4++" version would still be getting the (original) "System extension cannot be used" complaint pop-up about the AppleUSBEthernetHost kext being "installed improperly" and not loading, no? (Edit: If they are on a 32-bit only Mac, or are subject to the same conditions where they got the error originally - i.e. on other Macs running newer OSes than Snow Leopard.)

I never got that error from iTunes 11.3.1... thought I don't know why. Maybe it was a warning and the kext was loading anyway? I agree that if the kext in 11.4 is still 64-bit only, the error should be occurring. I may try to clean iTunes off completely and install the latest 11.4 version tonight.

"I never got that error from iTunes 11.3.1 ... thought I don't know why. Maybe it was a warning and the kext was loading anyway? I agree that if the kext in 11.4 is still 64-bit only, the error should be occurring."

I never saw the error until (the old) 11.4.

I got the pop-up on two Macs - both my home Mac Pro on 10.6.8, but also on a 2011 Mac mini at work running Mac OS X Server 10.8.4. Obviously both of them 64-bit capable machines.

"I may try to clean iTunes off completely and install the latest 11.4 version tonight."

Would be intriguing to see the results. Go forth, brave warrior 😉

I believe the warning was related to accumulated detritus within the AppleUSBEthernetHost. Greg identified some residual symlinks or files which weren't getting cleaned up in the system extension cannot be used AppleUSBEthernetHost.kext thread:

When iTunes 11.4 was installed via Software Update/App Store, it removed CodeDirectory/CodeRequirements/CodeSignature but it did not remove the corresponding symbolic links. Presumably that is what triggered the "cannot be used" pop-up message.

Most of us removed the kext in its entirety and reinstalled AppleUSBEthernetHost in one way or another. It still doesn't load on 32-bit machines, but it is now installed correctly and the popup is gone.

I did not delete any files. I just followed Airmoe's link and downloaded and reinstalled iTunes 11.4. Everything appears to be working fine now. Thank you. (2006 iMac 4,1 with 2 GHz Intel Core Duo and OS 10.6.8).

"I believe the warning was related to accumulated detritus within the AppleUSBEthernetHost.kext"

Well, that's an interesting theory. Because the pop-up is sorta ambiguous. There is "installed improperly" and "cannot be used".

The latter certainly applies if there's a 64-bit only kext on a 32-bit only system! You could also claim installing a kext that is for the wrong architecture is also "installed improperly" 🙂

The question is though, if the kext isn't loaded, what does it impact? There must be something that uses that thing!

Isn't it just a driver for the Apple USB Ethernet adapter? Why would iTunes even include such a thing?

(I use one of those on a production Mac mini at work with Mac OS X Server 10.8.4 ... hmmn. Strangely, I updated to iTunes 11.4 on it, got the pop-up error, removed the .kext, reinstalled from the .dmg - AppleUSBEthernetHost.kext loaded and the driver/interface still works. Weird!)

... and, lo and behold, look:

[20:08] nightowl:/<1>Library/Extensions % pwd

/System/Library/Extensions

[20:13] nightowl:/<1>Library/Extensions % sudo kextload -v AppleUSBEthernetHost.kext

Requesting load of /System/Library/Extensions/AppleUSBEthernetHost.kext.

/System/Library/Extensions/AppleUSBEthernetHost.kext failed to load - (libkern/kext) link error; check the system/kernel logs for errors or try kextutil(8).

[20:20] nightowl:/<1>Library/Extensions % sudo kextutil -v AppleUSBEthernetHost.kext

/System/Library/Extensions/AppleUSBEthernetHost.kext appears to be loadable (not including linkage for on-disk libraries).

Loading /System/Library/Extensions/AppleUSBEthernetHost.kext.

(kernel) kxld[com.apple.macos.driver.AppleUSBEthernetHost]: The Mach-O file is malformed: Invalid segment type in MH_KEXT_BUNDLE kext: 42.

(kernel) Can't load kext com.apple.macos.driver.AppleUSBEthernetHost - link failed.

(kernel) Failed to load executable for kext com.apple.macos.driver.AppleUSBEthernetHost.

(kernel) Kext com.apple.macos.driver.AppleUSBEthernetHost failed to load (0xdc008016).

(kernel) Failed to load kext com.apple.macos.driver.AppleUSBEthernetHost (error 0xdc008016).

Failed to load /System/Library/Extensions/AppleUSBEthernetHost.kext - (libkern/kext) link error

Failed to load /System/Library/Extensions/AppleUSBEthernetHost.kext - (libkern/kext) link error.

Check library declarations for your kext with kextlibs(8).

I can't even load it on my 64-bit Mac Pro! 😠

A quick Google search finds

--

https://developer.apple.com/library/mac/releasenotes/DeveloperTools/RN-Xcode/xc4 _release_notes/xc4_release_notes.html

Xcode 4.6.2 Release Notes

Changes

Building: Kernel Extensions

Kernel extensions (kexts) built with Xcode 4.6.1 and 4.6.2 fail to load on OS X 10.6 and 10.7, and this error message appears in the console:

To build kexts that load on OS X 10.6 and 10.7, on the targets that build the kexts, set the OS X Deployment Target build setting to OS X 10.6. 13645170

--

So who knows what the **** they built this thing on ... 😮

@Greg: I have a 2006 Mini, Core Duo, running 10.6.8. I Software Updated to 11.4, got the USB message, and sync was busted for my iPod Touch gen4. Applied cwa2's fix, and 11.3.1 worked fine again. I let Software Update install 11.4 again yesterday, thinking if it was broke, I could still apply cwa2's fix, but now all is well. Here's the file info you asked about:

ls -lF "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEt hernetHost"

-rwxr-xr-x 1 root wheel 63024 Jul 29 15:48 /System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEth ernetHost*

ls -lcF "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEt hernetHost"

-rwxr-xr-x 1 root wheel 63024 Sep 26 13:47 /System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEth ernetHost*

file "/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEt hernetHost"

/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS/AppleUSBEthe rnetHost: Mach-O 64-bit kext bundle x86_64

Took the plunge and installed the new version. Working with no problems so far.