Booting your Mac has the following key configuration options to boot in different modes by first pressing the Mac's boot key, except in cases where it is indicated not to, and immediately press these key combinations until some content appears on the screen:

  • Cmd (⌘) + R: Starts the Mac in recovery mode with access to the "macOS Utilities" and other tools that allow you to manage the disk, access the console, define a WIFI connection, and of course perform an OS recovery. From here you can install the latest version that was installed on the Mac, as long as it is available. In case of disk error or other situations this recovery may not be possible and you may have to perform an installation of macOS from scratch.
  • Uppercase (⇧): Starts the installed macOS system in safe mode. The use of firmware password is disabled if it is specified.
  • Option (⌥) or Alt: Launch the Boot Manager to choose the available boot disk or volume. Firmware password is required if specified.
  • Option (⌥) + Cmd (⌘) + P + R: Reset NVRAM (stores certain display settings, boot disk selection, time zone, sound volume, etc.) or PRAM (RAM parameters).
  • T: initial the system in destination disk mode, which is used to transfer files on two Macs leaving a computer as an external hard disk drive; very useful for backup and recovery processes. The use of firmware password is disabled if it is specified.
  • Cmd (⌘) + V: Starts the macOS in verbose mode. The use of firmware password is disabled if it is specified.
  • Option (⌥) + Cmd (⌘) + R: This combination is used to update your macOS to the latest version of macOS compatible with your Mac.
  • Shift (⇧) + Option (⌥) + Cmd (⌘) + R: This combination is used to install the version of macOS that came in origin on the Mac.
  • Shift (⇧) + Ctrl + Option (⌥) for 7 seconds, without having pressed the Mac boot before and ensuring that the Mac is turned off, and without releasing these three keys press for another 7 seconds the boot key: reset the SMC (System Management Controller). Very useful if your Mac won't boot. Your Mac must be unplugged for at least 30 seconds beforehand to release electricity from the electronics, and you can plug it in before running this key combination.