Q: system extension cannot be used AppleUSBEthernetHost.kext

OK, in the meantime I have another "data point" in this mystery.

I, too, made the mistake of allowing Software Update to update iTunes to 11.4 and received the "system extension cannot be used" error message.  On the first page of this thread tingly made the suggestion to delete the .kext, download iTunes from the Apple site and install it.  I did that before realizing that there were four more pages to come, i.e., that this might not be the generally accepted solution; for me, however, it seems to work.

The error message did not appear during installation.  iTunes 11.4 started without a problem and both my iPhone 4S and my 2nd generation iPad appeared under Devices, both being connected by Wi-Fi.  I plugged each of them into my MacBook Pro using a USB cable and synchronized each with iTunes without any problem.  I checked both devices.  New photos appeared on each, so the sync apparently worked.  I did have a problem trying to make a backup to my computer after the sync, which I wanted because the automatic backup is being made to iCloud and I wanted a fuller backup.  iTunes reported that it could not start the sync on the device, despite the fact that it was still displayed under Devices.  I was able to "solve" this problem by ejecting the device, powering it off, then back on, then reconnecting it via USB cable.  After ejecting both devices, then connecting them to power sources, they did not automatically appear under Devices, even though they were connected to Wi-Fi.  I'm not sure whether that is expected behavior; however, when I restarted iTunes they both appeared.  It seems that tingly's suggestion worked for me.

I am running OS X 10.7.5 and iOS 7.1.2.

Richard

I have done the fix as well and I can't sync or back up my iPhone 5. My iMac is running 10.6.8.

FYI - I have been contacted by someone at Apple and have been asked to talk to him via telephone to provide data to Apple Engineering about this.  So they are on the case.

It's difficult for somebody who is not involved in the development or support of software to determine the significance of a message in a log.  Sometimes it is generated at a place in a module which should never be reached.  In those cases at the very least they warn development that the matter should be investigated.  Sometimes, such messages can help to explain why subsequent messages are being issued.  In still other cases, the message is expected, given that the hardware or operating system does not support certain features, or some optional software has not been installed.

That said, these messages should be documented, and at some point in the process of supporting customers logs should be consulted to determine exactly what is happening in a machine when it isn't doing something that it should, or when it displays a message intended for the user.  I can understand that most agents involved in first-level support are incapable of interpreting the contents of a log.  What I do not understand, though, is, why they insist on running a customer who has evidently examined the console log through their idiot's checklist instead of passing him on to the level of support that deals with problems on that level.  That just frustrates a potential troubleshooting ally, somebody who might also be able to subsequently help others to understand and work around the cause of the problem.

Having evidently been lucky that the simple fix of deleting the .kext and installing iTunes 11.4 from the Apple site works -- keeping my fingers crossed! -- I can say that I will not upgrade from OS X 10.7.5 Lion and iOS 7.1.2 until Apple fixes this problem to the satisfaction (almost typed "satisfiction", a Freudian slip on my part) of those running Mavericks who can no longer synchronize or use their iToys.

Greg Earle wrote:

 

FYI - I have been contacted by someone at Apple and have been asked to talk to him via telephone to provide data to Apple Engineering about this.  So they are on the case.

If there is any doubt that Apple Support does not read and monitor these communities, this and my past experiences show that not to be the case. My experience with the mid-2011 MBA EFI 2.9/2.9.1 issue is very similar.

If you are on the phone, and not happy with the current person, one option is to ask for an escalation. My experiences have been excellent and the resolution is usually quick and painless after such a request. The first level person usually follows a "canned" prescription to solve a problem. An escalation will get you someone more experienced and well versed in technical issue resolution, but do not expect the principal architect of iTunes or iPhone to be answering your calls either.

@bwanabonga,

I understand a new release of Mavericks has just been made available.  Did you install it?  If so, has that affected the problems that you are experiencing in any way?  Any new hints in the console log?

I fixed it by opening up a Finder browser where I found AppleUSBEthernetHost.kext and dragged it into the trash can.  Then, I downloaded and installed itunes from https://www.apple.com/itunes/download

This worked for me. I'm running OS 10.6.8 on my MacBook. After updating iTunes via software update and getting the error message, I never opened iTunes. Used Tingly's fix and haven't gotten another error message. All seems to be working well.

Yes, as I said, Tingly's fix worked for me, too.  I notice, though, that you and I are running older versions of OS X than some who report problems after doing what we did.  That's why I would be interested in knowing (a) whether the problems with the fix only occur in Mountain Lion (one major version newer than my OS X 10.7) and/or Mavericks (two major versions older) and, for those encountering problems with the fix who are running Mavericks, whether the latest release of 10.9 solves the problems.

Just to relate my experience on a Mid-2011 iMac running Mac OS 10.7.5 (Lion)

On Wednesday, 17 Sep 14, I installed iTunes 11.4 to replace my previous iTunes 10 install. The same error message popped up. Today after reading this thread, I took the following steps:

1. Located the affected kext file and moved it to the trash (it was version 7.0 dated October 2009)

2. Re-installed iTunes 11.4 from the dmg.

3. Checked to see if the kext file had been installed and it had; now it was still version 7.0, but it has a date from July 2014.

4. Emptied the trash and shut down the iMac.

5. Re-booted the iMac and launched iTunes; no error message.

6. Connected my iPhone 3GS via USB and synced without a problem.

Same issue running 10.6.8 on intel tower. Start or restart I get the error message.

Easy solution... Apple should just provide a fix under Software Update

Luckily this is not annoying at all. Oh. Wait.

Anybody here who experienced the problem before the latest version of Mavericks, released just a few days ago?  If so, did the new update solve the problem.  Apple sometimes "quietly" fixes problems that it never acknowledges, allowing customers to work themselves into a tizzy discussing among themselves in such forums, while engineers  quietly put the finishing touches on software that was (accidentally) released "half-baked".