It’s unclear what’s causing the problem, but the Galaxy S10 uses an ultrasonic sensor to detect fingerprint ridges. Plastic or silicon screen protectors can stymie it, so Samsung recommended that buyers use approved protective devices. This does not explain why the system allows access to unregistered fingerprints, however, so Engadget contacted Samsung for more information.

Samsung initially told the British edition of the sun, which first reported the problem, that it was looking into the issue. Before the patch comes, you can use Samsung face unlock, but it had its own problems. For now, maybe just use the good old code.

Update 17/10/2019 5: 52 AM ET: Samsung told Engadget that “We are investigating this internally. We encourage all customers to use Samsung authorized accessories specifically designed for Samsung products.”