It might sound like the latest title from an Amazon-topping sci-fi author, but it's actually an error message that's been killing off a great many iPhone 6 handsets.
It appears that the latest iOS 9 update is causing many handsets that have had their ID Touch home button replaced by a non-official Apple technician to effectively 'die'.
"The problem occurs if the repairer changes the home button or the cable", iFixit editor Kyle Wiens told The Guardian. "Following the software upgrade the phone in effect checks to make sure it is still using the original components, and if it isn’t, it simply locks out the phone. There is no warning, and there’s no way that I know of to bring it back to life."
A scan of Apple's help forums reveal that the problem has been reported for some time, but the latest iOS update seems to be affecting a much greater number of repaired iPhone 6 users.
Many users are complaining that, given Apple's limited number of official retail and repair outlets they are forced to turn to local technology specialists to repair broken home buttons. Upon updating their iOS in order to install new apps, they are then met with the 'Error 53' message, and told they aren't covered by their warranty.
So, best not take the cheap option should your iPhone home button break.