A comprehensive reference for every boot mode, key combo, and recovery option available on Intel and Apple Silicon Macs.

Download Bootable Installer

This section outlines how to download a specific version of MacOS and install on a flash drive which can be used to boot the computer. Please note this is not necessary and is mainly useful if you need to reset multiple machines at once since it saves having to download the OS each time.

1. List available installers

softwareupdate --list-full-installers

2. Download the installer

# Monterey (supports 2017+ Intel & M1)
softwareupdate --fetch-full-installer --full-installer-version 12.7.6
 
# Ventura
softwareupdate --fetch-full-installer --full-installer-version 13.7.8
 
# Sonoma
softwareupdate --fetch-full-installer --full-installer-version 14.8.5

3. Format the USB drive

# find your drive
diskutil list
 
# format as APFS (replace diskN with your drive)
# NOTE: usually it will be disk4 or disk5
diskutil eraseDisk APFS "USB Drive" /dev/diskN

4. Create bootable installer

# Monterey
sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia \
  --volume /Volumes/USB\ Drive
 
# Ventura
sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia \
  --volume /Volumes/USB\ Drive
 
# Sonoma
sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia \
  --volume /Volumes/USB\ Drive

5. Boot from USB

• Intel Mac: hold Option key at startup
• M1/M2 Mac: hold Power button until “Loading startup options” appears Then open Disk Utility → erase internal drive as APFS → install macOS.

Safe Mode

Boots macOS with minimal drivers/extensions, clears caches, and runs a basic disk check.

Confirming Safe Boot

• Login screen: “Safe Boot” appears in red in the top-right corner
• After login: Apple menu → About This Mac → System Report → Software → Boot Mode: Safe

Recovery Mode

Access Disk Utility, reinstall macOS, Terminal, and more.

Internet Recovery

If the local recovery partition is missing or corrupted (e.g., blinking folder icon):

Requires Wi-Fi or Ethernet. You’ll see a spinning globe if it’s working.

Startup Manager (Boot Picker)

Hold Option (⌥) at startup to select a boot volume — internal drive, USB installer, external disk, or network boot.

Verbose Mode

Hold Cmd + V at startup. Shows the full kernel boot log instead of the Apple logo. Useful for diagnosing where the boot process is failing.

Single User Mode (Intel Only)

Hold Cmd + S at startup. Drops into a root shell before the GUI loads. Minimal Unix environment for disk repair, filesystem checks, etc.

Common commands in single user mode:

# Check and repair filesystem
/sbin/fsck -fy

# Mount root filesystem as read/write
/sbin/mount -uw /

# Reboot
reboot

Note: Disabled on Macs with T2 chip if Secure Boot is set to Full Security. You may need to lower it via Recovery Mode first.

Target Disk Mode

Hold T at startup. The Mac acts as an external drive over Thunderbolt or FireWire, letting another Mac mount and access its disk directly.

• Apple Silicon equivalent: In Recovery, go to Sharing → enable Share Disk

NVRAM / PRAM Reset (Intel Only)

Hold Cmd + Option + P + R at startup for ~20 seconds.

Resets firmware-level settings:

• Startup disk selection
• Display resolution
• Audio volume
• Time zone
• Kernel panic logging

Apple Silicon Macs reset NVRAM automatically when needed during startup.

SMC Reset (Intel Only)

Resets the System Management Controller — handles fans, power, thermal management, charging, sleep, and keyboard backlighting.

MacBook (with T2 chip)

1. Shut down
2. Hold Left Ctrl + Left Option + Left Shift for 7 seconds
3. While still holding those keys, also hold the Power button for 7 more seconds
4. Release all keys, wait a few seconds, then power on

MacBook (without T2)

1. Shut down
2. Hold Left Shift + Left Ctrl + Left Option + Power for 10 seconds
3. Release all, then power on

Desktop (iMac, Mac mini, Mac Pro)

1. Shut down
2. Unplug power for 15 seconds
3. Plug back in, wait 5 seconds, then power on

Apple Silicon Macs have no SMC — equivalent resets happen by shutting down and waiting 30 seconds.

Diagnostics Mode

Tests hardware (RAM, logic board, sensors, etc.).

Internet-based diagnostics: Option + D (Intel) if local diagnostics are unavailable.

Erase All Content and Settings (No Reboot Required)

Available on macOS Monterey+ with T2 or Apple Silicon:

System Settings → General → Transfer or Reset → Erase All Content and Settings

Factory resets without needing Recovery Mode. Wipes user data, re-signs the OS, and presents the setup assistant.

EFI Shell (Advanced)

Macs use EFI/UEFI firmware — there is no traditional BIOS screen. However, you can boot into an EFI shell:

1. Format a USB drive as FAT32
2. Place a UEFI shell binary at /EFI/BOOT/BOOTx64.efi
3. Hold Option at boot and select the USB
4. You now have a command-line interface to the firmware

DFU Mode & Apple Configurator 2 (Lowest Level)

The nuclear option. Reflashes T2 chip firmware and UEFI. Requires a second Mac with Apple Configurator 2 (free from App Store) and a data-capable USB cable.

MacBook Pro / MacBook Air (T2, 2018+)

1. Shut down, connect USB-C to host Mac
2. Press and hold Power for 1 second
3. While still holding Power, also hold Left Shift + Left Ctrl + Left Option
4. Hold all 4 keys for ~10 seconds, then release
5. Screen stays black — Apple Configurator should detect it

iMac (T2, 2020+)

1. Unplug power completely
2. Connect USB-C to host Mac
3. Hold Power while plugging power back in
4. Keep holding Power for ~3 seconds, then release

Mac mini (T2, 2018+)

1. Unplug power
2. Connect USB-C (port closest to HDMI) to host Mac
3. Hold Power while plugging power back in
4. Keep holding for ~3 seconds, then release

Mac Pro (2019, Tower/Rack)

1. Unplug power
2. Connect USB-C (port on top near power button) to host Mac
3. Hold Power while plugging power back in
4. Hold for ~3 seconds, then release

Revive vs Restore

• Revive: Attempts to repair firmware without erasing data — try this first
• Restore: Full wipe + firmware reflash — last resort

Older Intel Macs (No T2)

DFU mode is not available. Recovery options are limited to Internet Recovery, USB installer, or hardware repair.

Blinking Folder with Question Mark

This means the Mac cannot find a bootable operating system.

Causes

• Disk has been erased or is corrupted
• Boot partition is missing
• Drive has failed

Solutions (in order)

1. NVRAM reset — Cmd + Option + P + R (may fix incorrect boot disk selection)
2. Internet Recovery — Cmd + Option + R (download and reinstall macOS)
3. USB installer — Boot from Option key, install from USB
4. DFU restore — If firmware itself is corrupted

Quick Reference Table