I like to connect my iPad (3rd Gen; Wi-Fi + Cellular) to iTunes in my macOS (10.12.5) using the USB cable. This fails but the funny thing is that it works fine when I enable the USB connection to be forwarded to my Windows 10 running on the same machine under VMWare Fusion (8.5.8). This rules out any hardware problem I think. It syncs and backups fine under VMWare.
> Assertion failure: error == noErr (-402653052) > failed to connect to USB device 0x6100003940f0, UDID 340a25595bfa87ccb0d4fd3f7bee6c5ea4470d80 (0xE8000084)