iPhone restarts on its own: when Apple’s security function causes problems

A new security feature in iOS 18 offers more security, but causes problems in some use cases. Security researchers have analyzed that if an iPhone is not unlocked for a period of 72 hours, it will automatically restart. The independent restart also disconnects the mobile connection if the SIM PIN is set. This is often likely to happen in Germany if an older, physical SIM card is used in the iPhone.

Advertisement

iPhone no longer accessible

This means that the iPhone can no longer be accessed by phone and the location can only be accessed temporarily and to a limited extent through Apple’s “Find My?” Can be tracked through network. This can cause problems in both personal and business use: If a field worker places an iPhone at the charging station in the office on Friday afternoon and takes it back to the next appointment on Monday afternoon without unlocking it first, it is already Has restarted. The phone cannot be contacted as usual for calls.

If the iPhone is used solely as an emergency phone with location tracking, for example for seniors or small children in the family, it is not only calls that fail: cut-off cellular connections also affect location. Limits tracking. After the iPhone restarts, it goes into AirTag-like mode, but then it only displays “Find My?” Can be accessed through for approximately 24 hours. roughly space, As security researcher Jiska Klaassen pointed out after her detailed analysis of the function,

Location determination may also become less accurate during this period, especially if the iPhone is in less densely populated areas. Even normal ‘where-is’ functions like playing sound do not work in this mode.

Solution: Disable SIM PIN

Apple has so far neither confirmed nor denied this function, which was apparently introduced with iOS 18.0. Originally it was explicitly designed to have a period of inactivity of 7 days, iOS 18.1 has reduced this to 3 days. Users cannot turn off automatic reboot.

Top 5: The best battery-powered projectors in the test

However, users can prevent the mobile connection from being disconnected: if the SIM PIN is not activated, the iPhone logs back into the mobile network and remains accessible even after a restart. The option can be found in “Settings > Cellular > SIM PIN” or “Settings > Cellular > (SIM name) > SIM PIN”. Of course, the SIM card is no longer protected by its own PIN, so a thief can read it and continue using it unless it is blocked by the mobile phone provider.

In normal everyday use, users should practically never encounter inactivity restarts, after all, the iPhone regularly unlocks and resets the timer. And if it is left without an additional power supply, the battery will typically drain before the 72 hours are complete.

(lb)