As an important final note, always ensure you have backed up your device using iTunes or Finder before attempting any jailbreak. While checkra1n is generally safe, having a backup is the only way to guarantee you won't lose your data.

The primary reason for this pop-up is rooted in how the jailbreak tool operates. checkra1n is built on the “checkm8” bootrom exploit, which targets the iPhone’s hardware before the main iOS even loads. Executing this hack successfully requires extremely precise USB timing and direct device access that a standard operating system’s generic drivers aren’t designed to provide.