If you have scars, tattoos and other obstructions on your wrists, you could have some problems with Apple Watch. That's because those things can make it difficult for the watch to read your blood pressure or even sense skin contact.
Apple blog iMore tested the problem out and found that solid, dark-colored tattoos tend to give Apple Watch the most problems. It also wrote "that prominent scars and other potential skin aberrations can trip the Watch's sensors."
That could give users fits when they're trying to use Apple Health features. And, that's not all. This little defect could get annoying really fast, because the Apple Watch can automatically lock when it doesn't recognize skin contact.