Follow these steps on older computers that have neither Apple silicon nor the Apple T2 Security Chip.

Laptop computer

1. Shut down your Mac.

2. On your built-in keyboard, press and hold all of these keys:

   • Shift on the left side of your keyboard

   • Control on the left side of your keyboard

   • Option (Alt) on the left side of your keyboard

3. While holding all three keys, press and hold the power button as well.

   

4. Keep holding all four keys for 10 seconds.

5. Release all keys, then press the power button to turn on your Mac.

If your Mac isn't a laptop computer, follow these steps:

1. Shut down your Mac, then unplug the power cord.

2. Wait 15 seconds, then plug the power cord back in.

3. Wait 5 seconds, then press the power button to turn on your Mac.