Chosen Solution
When I update my phone to IOS 11 the touch ID always show me ‘unable to complete touch ID setup -I’ve delet all setting -return to ios 10 -i’ve not open or fix any thing in the device New one) Still not working
Sometimes I’ve seen touch ID restarting to work after 3/4 hard resets performed. I ignore the reason behind such behaviour but by experience I’d try that too before surrender.
If you are sure nobody has opened the phone and performed unauthorized repairs, only Apple can fix this.
