An Apple error message is rendering some iPhones that have been repaired by non-authorized repair shops useless, as Apple tries to exert more control over repairs to its products. iPhone owners have been complaining online that when upgrading their phones to the latest software, they received "Error 53" messages that lock them out of their devices and the data stored on them.

According to Apple's website, the Error 53 message means the phone’s fingerprint sensor is either broken or has been replaced. The company says that can happen after "an unauthorized or faulty screen replacement."

Apple confirmed that the Error 53 is the result of security checks designed to protect customers. Apple's software checks that the fingerprint sensor matches the device’s other components. If the check fails, "Touch ID, including for Apple Pay use, is disabled. This security measure is necessary to protect your device and prevent a fraudulent Touch ID sensor from being used, "Apple said.

Independent repair shops often replace the fingerprint sensor or its small cable when replacing cracked screens or broken home buttons on iPhones.