Error 53: iPhone-killing software update, explained

The iPhone 6 is shown in Toronto, on Friday, Sept. 19, 2014. (Hannah Yoon / THE CANADIAN PRESS)

Some iPhone and iPad users have watched in horror as their costly device is rendered useless after upgrading the operating system.

Apple users are reporting that their iPhones and iPads are disabled and display an "error 53" message after upgrading to the latest version of iOS 9.

The problem affects devices that feature its Touch ID fingerprint recognition, Apple says, and can occur after an "unauthorized" or faulty screen replacement. In other words, if an iPhone user has their device repaired somewhere other than an Apple Store or Apple service centre, they could run into smartphone-crippling problems when they update it.

The company says, when a system check during a software update reveals the iPhone or iPad Touch ID sensor doesn't match the device's other components, the update fails.

Technology experts say it "bricks" the devices – meaning they are rendered as useful as a brick.

"If the check on Touch ID fails, your update won't finish," Apple says on its support website. "You'll see a Connect to iTunes screen on your device or a message like this in iTunes on your computer: The iPhone [device name] could not be restored. An unknown error occurred (53)."

Apple suggests that users who encounter an error 53 message should force a restart of their device. If that doesn’t work, they should contact Apple Support.

The company suggests that if the screen or any other part of the iPhone or iPad was replaced somewhere other than an authorized Apple dealer, users should contact Apple Support about "pricing information for out-of-warranty repairs."

Some iPhone and iPad users have reported that they've lost all of their data after the error 53 message popped up on their device and they were told there's no way to fix the problem. Some users say they've either brought their disabled device into an Apple store, where they've received a new one, or have simply gone out and purchased a new one.

"After an hour and 15 minute phone call, the ‘senior’ technician told me to take it back to the store and get another one. I guess 53 = DEAD," one iPhone user wrote on an Apple support website.

In a statement to The Guardian, Apple said: "This security measure is necessary to protect your device and prevent a fraudulent Touch ID sensor from being used. If a customer encounters Error 53, we encourage them to contact Apple Support."

As anger over the disabling of iPhones and iPads grows, lawyers in the U.S. and the U.K. have reportedly said they're considering bringing forward a class action lawsuit against the technology giant, claiming that the company may be acting illegally.