Craig Federighi demoed the Face ID feature but his device troubled to recognize the executive for unlocking the phone. Users can see the shaky moment from the event over the internet.

Face ID system introduced by Apple in iPhone X uses TrueDepth camera to ensure only the right user gets the access of the phone. Dot projector draws the map of the face shape in 3D with invisible 30,000 dots. Infrared camera later has to read the pattern provided and uses 2 data sets in order to confirm the match. Flood Illuminator is also part of the Face ID system as its being used to identify user if he is standing in the dark.

Any of the above mentioned features might not have worked when Craig Federighi tried first but it worked on the second attempt. And not just the stage, the iPhone X was showing problems at post event demo area.