1. download AppleUSBEthernetHost.kext.zip from https://discussions.apple.com/thread/4386838
and unzip it (my MBP unziped it during downloading automatically).
2. create a new dir under your hard disk 'Macintosh HD', such as USBHotspotFile and save AppleUSBEthernetHost.kext under it. You may keep it there forever as every time you upgrade iTune, you may have to do this fix again. The problem had been reported 1+ year ago, but Apple never tried to fix it. In step-9 below, I assume you have done this step-2.
3. enable su (root) user:
4. bring up Terminal: Applications->Utilities->Terminal, which is a unix command line interface. After enter a command string, you always press <return> key to issue it. Please note that you can just use your mouse highlight following commands in step-5 to step-10, one at a time, and drag-drop it to Termianl's command prompt position and press <return>
5. issue command: su
6. system will ask you for Password:, just enter the password you set in above step-3
7. issue command: cd /System/Library/Extensions/AppleUSBEthernetHost.kext/Contents/MacOS
8. issue command: mv AppleUSBEthernetHost AppleUSBEthernetHost.bad
9. issue command: cp /USBHotspotFile/AppleUSBEthernetHost.kext/Contents/MacOS ./
10. issue command: ls -l
11. you will see system displaying something like following for above command:
-rwxr-xr-x@ 1 root wheel 180760 Dec 1 23:07 AppleUSBEthernetHost
-rwxr-xr-x 1 root wheel 118720 Aug 10 18:02 AppleUSBEthernetHost.bad
here you can see that the correct file has size 180760 (which is what you will get from downloaded .zip file) and the incorrect file has size 118720 (which is what I got from ITune 11.0 upgrade)
12. PLEASE REMEMBER do above step-3 again, but for DISABLE su (root) user.
Hope this will reslove your problem. Cood Luck!🙂