If you’ve just updated iTunes on your Windows PC to version 11.1.4 and are no longer able to sync your iPhone or iPad, it’s likely that the new software has disrupted the drivers for your iOS device.
To repair the problem:
1. Shutdown iTunes.
2. Connect your iOS device to your PC via USB cable.
3. In Explorer, navigate to this folder:
C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers\
4. Locate and right-click the file called usbaapl64.inf and select Install from the menu.
5. Reboot your PC and the problem should be resolved.