Apple iOS 18 Secretly Reboots Idle iPhones After 72 Hours
Apple's latest iOS 18 update includes a hidden security feature that automatically reboots iPhones if they remain unlocked for three days. This inactivity reboot locks encryption keys in the secure enclave, making it significantly harder for forensic tools to extract data.
Apple’s iOS 18 update introduces a hidden "inactivity reboot" feature that automatically restarts an iPhone if it remains unlocked for 72 hours. Security researcher Jiska Classen demonstrates this behavior in a new video, showing exactly how the device powers itself down after three days of inactivity. Digital forensics company Magnet Forensics confirms this three-day timer, which initially caused confusion among law enforcement officers who noticed devices mysteriously rebooting.
This feature serves as a powerful anti-theft measure by forcing the iPhone into a more secure state. When the device restarts, it locks the user's encryption keys inside the secure enclave chip. As a result, thieves or hackers cannot use cheaper, outdated forensic tools to extract data from a powered-on phone that they have physically stolen.
While this inactivity reboot makes data extraction more challenging for law enforcement, it does not completely lock out professional forensic analysts. Classen notes that the three-day window still provides ample time for authorities to coordinate with experts and access criminal devices. The feature ultimately shifts the iPhone into a "Before First Unlock" state, significantly raising the bar for anyone attempting to bypass the device's security.