Your iPhone may automatically switch to Recovery mode when an error or glitch makes the device inoperable. You can also deliberately enter Recovery mode by pushing a combination of the “Sleep/Wake” button and the “Home” button. An iPhone in Recovery mode has a black screen, and when you plug it into iTunes, it does not register with the software. Instead, an error box appears saying iTunes has detected an iPhone in Recovery mode and you must restore the device. However, if you enter Recovery mode by accident, you can exit the mode without restoring your device.
