I'm only asking this out of curiosity. I've noticed that when I use my Touch ID to pay with iPhone, or to unlock an app, it's much quicker and it always works. However, while unlocking the iPhone, sometimes I need to put my thumb 2 or 3 times till it unlocks. I noticed this happening with different iPhone models too.

Is there any explanation for this? May I just be wrong?

1 Answer 1


No. You may experience slower response times due to presence of moisture or dust on or under Touch ID sensor or finger/thumb respectively.

Cleaning/Drying the Touch ID sensor/finger usually resolves the lag issue.

iPhone 6s and later (excluding iPhone SE and all Touch ID equipped models of iPad) have a second generation Touch ID sensor which is much faster at recognizing finger/thumb geometry.

  • You're right. I know that. Didn't you notice this then, I mean what I described? Thank you. Commented May 6, 2019 at 18:29
  • @Antonio23249 I have noticed it too, but not exclusively with unlocking. I experienced it when there was moisture/dust on the sensor/under finger and cleaning/drying instantaneously resolved the lag.
    – Nimesh Neema
    Commented May 6, 2019 at 18:32
  • when my fingers are a bit wet or cold I usually opt to use the passcode. Which makes me think passcode oglers may choose rainy days in a bus stop to learn passcodes....(just a joke) Commented May 6, 2019 at 20:20

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