- Turn on your Mac, then immediately press and hold Command-R to start up from macOS Recovery.
- Select Disk Utility from the Utilities window, then click Continue.
- From the Disk Utility sidebar, select the volume that you're using, then choose File > Mount from the menu bar. (If the volume is already mounted, this option is dimmed.) Then enter your administrator password when prompted.
- Quit Disk Utility.
- Choose Terminal from the Utilities menu in the menu bar.
- You can now enter UNIX commands. When done, choose Apple () menu > Restart.
These steps replace the Command-S method, which doesn't work with the recommended settings on current Mac computers.
- Turn on your Mac, then immediately press and hold Command-V.
- Continue holding the keys until you see white text on the screen.
- You can now enter UNIX commands. To exit this mode and start up normally, type
reboot, then press Return.