Hi, I gave the same problem. Did u find a way to get this sorted? Any help would be appreciated thanks.
Have you tried restarting your phone and your computer and trying again? To restart your phone, press and hold the Home button and Sleep/Wake button (iPhone 6s or earlier) or Volume Down button (iPhone 7) till you see the Apple Logo appear on the screen. Once you see the Apple Logo, then you can release both buttons and allow the phone to continue to boot.
OF COURSE, I have rebooted both the device and the PC multiple times in this unnerving process! I rebooted the PC. Restarted the iPhone. Reinstalled the drivers. Deinstalled and reinstalled iTunes. Rebooting all along the way. I tried different USB ports. Tried different Apple cords. No change. Get the same "unknown error" message. Each time I borrowed my kid's Apple laptop and hooked the iPhone to that and the latest iTunes version there. I get an error message there, too ("unknown value"). Does anyone have any real fix to suggest?
Make sure you download and install the latest version of iTunes, currently 12.6.2: https://www.apple.com/itunes/download/
Start here:
When you uninstalled iTunes, did you do it completely like this?
Does anyone have any better suggestion .. this does not work.
did you update to iTunes 12.6.2 ?
Yes, and I still get the SAME error!!
An unknown error occurred (0xE8000015)
