Q: system extension cannot be used AppleUSBEthernetHost.kext

Got the same message when I updated tonight. Everything seems to be working OK, though. Also get another error message when in iTunes check for update.

Had the same thing just happen to my iMac.  I have Mountain Lion 10.8.5.

I found this older article. I guess this happens on occasion.  They probably didn't set the installer to overwrite properly. 

Anyways I tried this and it worked.  You are basically removing ( or renaming as I did) the old kext and then rerunning the iTunes installer which will then properly install the kext.

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

Screenshot (error msg) in first post doesnt show up, but i believe its same one i got today, after waking up from sleep:

The system extension “//System/Library/Extensions/AppleUSBEthernetHost.kext” was installed improperly and cannot be used. Please try reinstalling it, or contact the product’s vendor for an update.

I dont have any iDevice connected (i got usb keyboard and mouse, and webcam which is turned off).

One year old iMac with 10.9.4 osx.

I have not approved any (os) updates after last reset (couple days ago). Any other updates in that period is audio editing software (audacity) extension: mp3 export codec library, and a game (unturned) via steam.

I cant see any relation between those, and this is bugging me

I was having the same issue and had reinstalled iTunes a few times with no success. As an experiment, I redownloaded iTunes from Apple Site this morning and TURNED OFF my iPad. Turned it off not put it to sleep and reinstalled and all went well. I do not have an iPhone and the iPad is my only extra apple device. There was no message this time and so far so good.  Mark

Just got the same problem & posted it as "System extension cannot be used" after installing iTunes 11.4

Have any of you peeps found it stops things from working?  All I've tested so far is Time Machine backup to an external USB drive: seems to have worked fine.

I've tried all of my devices, (iPhone, iPad, etc) and have not found any problems. I did try and reinstall the new iTunes and got the same message. Just going to leave it alone for now since everything seems to be working fine. Have to believe Apple knows about the problem by now and we'll see a new update in the next day or two.

bwanabonga wrote:

 

Funny thing isn't it - the bloody vendor in this case is none other than Apple, so perhaps a representative will eventually comment here, or there will be a bug fix?

Apple support does not monitor these forums or participate in any way, shape or form. I'd expect a dot release to be rolled out over the next few days to resolve the issue.

Send Apple feedback. They won't answer, but at least will know there is a problem. If enough people send feedback, it may get the problem solved sooner.

Feedback

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

Yours is the quickest fix. I extracted the file with Pacifist and replaced it. It works, but takes a while to extract it.

There's more to it than this IMHO.  Here is my explanation:

If I go back in my Time Machine backups and restore the previous version before I installed iTunes 11.4, the version of that same kext was also listed as being "7.0" despite being older and twice the size (120400 bytes vs. 63024 bytes in the 11.4-installed version).

(The older version is "BuildVersion 305" and "SourceVersion 122000000000000"; the new 11.4 version is "BuildVersion 417" and "SourceVersion 113000000000000".)

The real problem is this:

/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/_CodeSignature used to contain

-rw-r--r--+ 1 root  wheel  172 Jan 31  2014 CodeDirectory

-rw-r--r--+ 1 root  wheel    92 Jan 31  2014 CodeRequirements

-rw-r--r--+ 1 root  wheel  1745 Jan 31  2014 CodeResources

-rw-r--r--+ 1 root  wheel  4064 Jan 31  2014 CodeSignature

/System/Library/Extensions/AppleUSBEthernetHost.kext/Contents used to contain symbolic links down into there:

lrwxr-xr-x+ 1 root  wheel    28 Jun 12  2012 CodeDirectory@ -> _CodeSignature/CodeDirectory

lrwxr-xr-x+ 1 root  wheel    31 Jun 12  2012 CodeRequirements@ -> _CodeSignature/CodeRequirements

lrwxr-xr-x+ 1 root  wheel    28 Jun 12  2012 CodeSignature@ -> _CodeSignature/CodeSignature

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.

Trashing the kext and installing it from the downloaded 11.4 .dmg does not create the symbolic links, thus avoiding the problem.

Obviously rolling back to the previous (Jan 2014) kext will fix the problem as well as the symbolic links point to files that exist.

(I'm really curious to know what happened between BuildVersion 305 and BuildVersion 417 that caused it to shrink nearly by half.  It looks to me like the Code Signing stuff got ripped out - Lord knows why.)

Nice analysis. I opened a terminal window, changed directory to /System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/_CodeSignature and then deleted the bad symlinks:

sudo rm CodeRequirements CodeSignature

Then I ran the downloaded iTunes 11.4 installer. It didn't throw any errors this time, so, hopefully, the kernel extension will now be happily locked and loaded.

Cheers.