Erase and Reinstall macOS – Intel Mac

How to completely erase and reinstall macOS on an Intel-based Mac using Recovery Mode. This process wipes the entire drive and installs a fresh copy of macOS.

Note – This article covers Intel-based Macs only. For Apple Silicon Macs (M1, M2, M3, M4), see the Erase and Reinstall macOS – Apple Silicon Mac article.

When to Use This

• Reprovisioning a Mac for a new user
• Persistent macOS issues that can't be resolved with standard troubleshooting
• Preparing a Mac for return/trade-in/decommission
• Malware remediation requiring a clean install

Before You Start

1. Back up any user data that needs to be preserved (Time Machine, cloud sync, manual file copy)
2. Sign out of iCloud / Apple Account on the device if possible
3. Know the Mac's admin password (needed during Recovery)
4. Have a stable internet connection available (Wi-Fi or Ethernet) – required for Internet Recovery and reinstallation
5. Plug in the power adapter if using a MacBook
6. If a firmware password is set on the Mac, you'll need that password to boot into Recovery

Important – Erasing the disk permanently deletes all data. Verify backups are complete before proceeding.

How to Check if Your Mac is Intel-Based

Click the Apple menu → About This Mac.

• If you see "Processor" followed by an Intel chip name (e.g., Intel Core i5), it's an Intel Mac.
• If you see "Chip" followed by M1/M2/M3/M4, it's Apple Silicon – use the Apple Silicon article instead.

Method 1: Erase All Content and Settings (Quick Method)

Available on Intel Macs with a T2 Security Chip running macOS Monterey 12 or later. This is the fastest option when macOS is still bootable.

Note – Not all Intel Macs have a T2 chip. T2-equipped models include MacBook Air (2018+), MacBook Pro (2018+), Mac mini (2018), Mac Pro (2019), and iMac Pro. If your Mac doesn't have a T2 chip, skip to Method 2.

1. Open System Settings → General → Transfer or Reset
2. Click Erase All Content and Settings
3. Authenticate with the admin password
4. Optionally back up with Time Machine when prompted
5. Review the summary of what will be erased, then click Continue
6. Enter the Apple Account password to sign out of iCloud
7. Click Erase All Content & Settings to confirm

The Mac restarts, activates, and presents the Setup Assistant. If preparing for a new user, power off the Mac at the Setup Assistant screen.

Note – If macOS won't boot, the Mac doesn't have a T2 chip, or you need a full disk-level erase, use Method 2 below.

Method 2: Full Erase and Reinstall via Recovery Mode

Use this when macOS won't boot, the Mac lacks a T2 chip, or you need a complete disk-level wipe.

Step 1 – Boot into Recovery Mode

1. Click Apple menu → Restart (or press and hold the power button for 10 seconds to force shut down if macOS is unresponsive).
2. As the Mac restarts, immediately press and hold one of the following key combinations until you see the Apple logo or a spinning globe:

Key Combination	What It Does
Command (⌘) + R	Boots local Recovery – reinstalls the most recently installed macOS version
Option + Command + R	Internet Recovery – installs the latest compatible macOS for your Mac
Shift + Option + Command + R	Internet Recovery – installs the macOS that originally shipped with your Mac (or the closest available version)

Note – Use Option + Command + R if you want the newest macOS your Mac supports. Use Shift + Option + Command + R if you need the factory-original macOS version.

3. If prompted, connect to a Wi-Fi network using the Wi-Fi menu in the top-right corner, or connect an Ethernet cable.
4. If prompted for a firmware password, enter it.
5. If asked to select a volume to recover, select your startup disk (usually Macintosh HD) and click Next.
6. If asked to select an admin user, choose one, click Next, and enter the login password.
7. The Recovery utilities window will appear.

Step 2 – Erase the Disk with Disk Utility

1. In the Recovery utilities window, select Disk Utility and click Continue.
2. In the sidebar under Internal, select Macintosh HD.
3. Click the Erase button in the toolbar.
4. Set the following:
   • Name: Macintosh HD
   • Format: APFS (recommended for macOS High Sierra and later). Use Mac OS Extended (Journaled) if installing macOS Sierra or earlier.
5. Click Erase Volume Group if the button is shown. Otherwise, click Erase.

6. If prompted, enter Apple Account credentials.
7. When the erase completes, click Done.
8. Quit Disk Utility: Disk Utility menu → Quit Disk Utility to return to the Recovery utilities window.

Step 3 – Reinstall macOS

1. In the Recovery utilities window, select Reinstall macOS and click Continue.
2. Follow the on-screen instructions. Accept the license agreement.
3. When asked to select a disk, choose Macintosh HD.
4. Allow the installation to complete. The Mac may restart multiple times and the screen may appear blank for extended periods – this is normal.

Note – Do not close the lid or put the Mac to sleep during installation. Keep it plugged into power.

5. After installation completes, the Setup Assistant will appear. If provisioning for a new user, complete setup. If preparing for handoff, shut down the Mac at the Setup Assistant screen.

Recovery Mode Key Combinations – Which macOS Gets Installed?

Key Combination	macOS Version Installed	Best Use Case
⌘ + R	Most recently installed macOS	Standard reinstall – keeps the same macOS version
Option + ⌘ + R	Latest compatible macOS	Upgrade to the newest macOS the hardware supports
Shift + Option + ⌘ + R	Original shipping macOS (or closest available)	Downgrade to factory-original macOS

Note – Internet Recovery (Option and Shift+Option combos) requires an active internet connection via DHCP. It downloads the installer from Apple's servers.

Firmware Password

Some Intel Macs may have a firmware password set. This password is required to boot into Recovery or from an external disk. If the firmware password is unknown:

• The Mac will show a lock icon at startup when attempting Recovery
• The firmware password must be entered to proceed
• If the password is lost, the Mac must be taken to Apple or an Apple Authorized Service Provider for removal (proof of purchase required)

Note – Firmware passwords only apply to Intel Macs. Apple Silicon Macs use Activation Lock instead.

Troubleshooting

Issue	Cause	Resolution
Recovery Mode doesn't load (boots straight to macOS or login)	Key combo not pressed early enough or using wrong keyboard	Use the Mac's built-in keyboard. Restart and press Command + R immediately after pressing the power button. For wireless keyboards, wait a moment for the keyboard to connect before pressing.
Spinning globe with exclamation mark	Internet Recovery can't connect	Check internet connection. Try a different network. Avoid captive portals (hotel/public Wi-Fi). Try Ethernet instead of Wi-Fi. Try all three key combos.
Macintosh HD not visible in Disk Utility	Drive not detected or hardware failure	Unplug all external devices and retry. If the drive still doesn't appear, the Mac may need hardware service.
Erase fails in Disk Utility	Volume group issue	Try clicking Erase instead of Erase Volume Group. If that fails, try choosing View → Show All Devices, selecting the physical disk, and erasing the entire disk.
Lock icon appears at startup	Firmware password is set	Enter the firmware password. If unknown, the Mac must go to Apple or an AASP for removal.
"Erase All Content and Settings" not available	Mac doesn't have T2 chip, or running macOS Big Sur or earlier	Use Method 2 (Recovery Mode) instead
Installation says "an error occurred"	Network or server issue	Ensure a stable broadband connection using DHCP. Try a different network. Avoid 802.1X or PPPoE connections without a router handling PPPoE.
Mac won't activate after erase	No internet connection or Activation Lock	Connect to Wi-Fi or Ethernet. If Activation Lock is present, sign in with the Apple Account that was previously linked. If unknown, the original owner must remove the device from their Apple Account.
Wrong macOS version gets installed	Used the wrong Recovery key combo	Re-enter Recovery with the correct key combo. ⌘+R = latest installed; Option+⌘+R = latest compatible; Shift+Option+⌘+R = factory original.

Quick Reference

Task	Action
Boot to Recovery (Intel)	Restart → Immediately hold Command + R
Boot to Internet Recovery (latest macOS)	Restart → Immediately hold Option + Command + R
Boot to Internet Recovery (factory macOS)	Restart → Immediately hold Shift + Option + Command + R
Erase All Content and Settings (T2 chip only)	System Settings → General → Transfer or Reset → Erase All Content and Settings
Erase disk in Recovery	Disk Utility → Select Macintosh HD → Erase → APFS → Erase Volume Group
Reinstall macOS	Recovery utilities → Reinstall macOS → Select Macintosh HD → Follow prompts
Check if Mac is Intel	Apple menu → About This Mac → Look for "Processor" (Intel) vs. "Chip" (Apple Silicon)

References

• How to start up from macOS Recovery – Apple Support
• Use Disk Utility to erase an Intel-based Mac – Apple Support
• How to reinstall macOS – Apple Support
• Erase your Mac and reset it to factory settings – Apple Support
• Use macOS Recovery on an Intel-based Mac – Apple Support