How do I re-install apple mobile device support?

If this problem is troubling, you should visit the troubleshooting pages for mentioned device. The web link is: support.apple.com.

If the issue persists after applying the assistant to it, then you have no option but to remove and reinstall the Apple Mobile Device Service on Mac OS X. You’ll require authenticating with an administrator account and password to finish these steps.

The first thing is to disconnect your device from your Mac.

In the Finder, locate iTunes in the Applications folder and draw it to the Trash.

Move the iTunes icon to the Trash.

Choose Go > Go to Folder.

Enter /System/Library/Extensions and click go.

Position the file AppleMobileDevice.kext and pull it to the Trash.

Choose Go > Go to Folder.

Enter /Library/Receipts/ and click go.

Locate the file AppleMobileDeviceSupport.pkg and drag it to the Trash. If prompted, authenticate with the administrator password.

Important thing is that, mentioned file may not be present in Mac OS X v10.6 Snow Leopard; leave out to the next step for the case.

Restart the computer.

Choose Finder > Empty Trash and restart the computer.

Download and install the recent version of iTunes.

Connect your device to the Mac again and open iTunes

I hope this information is fruitful for you.

Good luck!