Your Mac’s hard drive is erased either through Erase All Content and Settings or via macOS Recovery with Disk Utility, depending on its chip and macOS version.
The steps for how to erase HD on Mac depend on one chip inside your machine. An Apple silicon Mac or one with a T2 Security Chip can run the built-in Erase All Content and Settings flow, while an Intel Mac needs the macOS Recovery and Disk Utility path. This guide covers both routes plus the procedure for external drives, so you land on the right method the first time.
The wrong approach wastes time and can leave the drive unusable until you reinstall macOS. Each method below names the exact settings and buttons to look for and flags the common mistakes that trip people up.
Should You Use Erase All Content and Settings?
If you are running macOS Monterey or later on a Mac with Apple silicon or an Apple T2 Security Chip, Erase All Content and Settings is the fastest way to wipe your startup disk. You do not need to boot into Recovery — the whole process runs from one dialog in System Settings.
The feature lives under System Settings > General > Transfer or Reset. Click Erase All Content and Settings, enter your Apple Account information when prompted, and the Mac handles the rest. On supported machines this is the recommended first choice because it requires fewer steps and automatically selects the correct format.
When the process finishes, the Mac restarts to a setup assistant screen, ready for a new owner or a fresh install. If this option does not appear in System Settings, or if you are using an Intel Mac without a T2 chip, the Recovery method below is the right next step.
How To Erase Your Startup Disk From macOS Recovery
For Intel-based Macs or any Mac where Erase All Content and Settings is unavailable, start up from macOS Recovery and use Disk Utility to erase the startup disk. Apple’s official documentation lists both APFS and Mac OS Extended (Journaled) as valid formats for this step.
Restart the Mac and hold Command+R until the Apple logo or a spinning globe appears. Once the recovery window loads, select Disk Utility from the utilities list and click Continue.
In Disk Utility’s sidebar you should see the startup volume named Macintosh HD unless it was renamed. Select it and check whether the Erase Volume Group button is available. If it is, click it — this removes the volume group including any paired system volumes in one operation. If only Erase appears, click that instead.
Choose APFS or Mac OS Extended (Journaled) from the Format menu. Apple’s official support documentation covers both as valid formats for Intel startup disks. Click Erase, wait for the process to finish, then quit Disk Utility.
From the Recovery menu you can now select Reinstall macOS if you want a working system again. The erase and the reinstall are separate steps — erasing alone leaves the drive empty.
If Macintosh HD does not appear in the sidebar, Apple recommends shutting down, disconnecting any nonessential devices, and trying again. If the disk still cannot be seen or erased after that, the Mac may need service.
Erasing an External Drive With Disk Utility
The same Disk Utility application handles external hard drives, SSDs, and USB drives, but you need to enable Show All Devices to see the physical storage device instead of just its volumes.
Open Disk Utility from /Applications/Utilities. From the menu bar choose View > Show All Devices. In the sidebar you will now see the physical device entry above its volume — select the device entry, not the volume.
Click Erase, then enter a name for the drive. Choose a format from the menu: APFS for SSDs and modern use, or Mac OS Extended (Journaled) for traditional hard drives and older Macs. If the Scheme option appears, set it to GUID Partition Map.
For sensitive data, click Security Options before the final erase to choose how many overwrite passes to write. A single fast pass is sufficient for most scenarios; multiple passes take longer but offer stronger assurance against data recovery. The available options depend on the drive type.
Click Erase, then Done when the process finishes.
| Method | Best For | Key Step |
|---|---|---|
| Erase All Content and Settings | Apple silicon or T2 Mac, macOS Monterey or newer | System Settings > General > Transfer or Reset > Erase All Content and Settings |
| Recovery + Disk Utility (Intel) | Intel-based Mac, any macOS version | Restart with Cmd+R, Disk Utility, select Macintosh HD, click Erase Volume Group |
| Recovery + Disk Utility (Apple Silicon) | Apple Silicon Mac when you cannot sign in | Hold power button, click Options, open Disk Utility, select startup volume, click Erase |
| Disk Utility for External Device | External hard drive, SSD, or USB drive | View > Show All Devices, select physical device, choose GUID Partition Map, erase |
| Disk Utility with Security Options | Sensitive data needing overwrite passes | In the Erase dialog, click Security Options and adjust the overwrite slider |
| Disk Utility when drive is missing | Any Mac where the startup drive does not appear | Shut down, disconnect non-essential devices, restart into Recovery and retry |
| Service path | Any Mac where no method detects the drive | Apple states the hardware may need service |
Erasing a Hard Drive on Mac: Four Common Mistakes
Four mistakes cause most failed erase attempts: erasing the wrong level in Disk Utility, forgetting to boot into Recovery, choosing the wrong format, and expecting the erase to also reinstall macOS.
The most frequent error is selecting the volume instead of the physical device in Disk Utility. This erases only that volume’s data but leaves the container and any other volumes intact. The fix is to enable View > Show All Devices so the full device entry appears in the sidebar.
Another common stumble is trying to erase the startup disk from a normally booted system. The startup disk cannot be fully erased while macOS is running from it. You must boot into macOS Recovery first, then open Disk Utility from there.
Format confusion also trips people up. APFS is the right choice for SSDs and modern Macs, while Mac OS Extended (Journaled) works on traditional hard drives and is listed by Apple alongside APFS for Intel startup disks. Using the wrong format can prevent the drive from booting or mounting correctly.
Finally, many people expect the erase step to reinstall macOS automatically. It does not. After erasing the startup disk, you need to quit Disk Utility and choose Reinstall macOS from the Recovery menu if you want the machine to boot again.
| Mistake | What Happens | How To Avoid |
|---|---|---|
| Erasing the volume instead of the device | Container and other volumes remain intact | Enable View > Show All Devices and select the top-level device entry |
| Forgetting to enable Show All Devices | Only volumes appear, device-level erase hidden | Choose View > Show All Devices from the menu bar before selecting |
| Booting normally instead of to Recovery | Startup disk in use, cannot erase | Restart and hold Command+R before the Apple logo |
| Using the wrong format | Drive may not boot or mount correctly | Use APFS for SSDs, Mac OS Extended or APFS for Intel startup disks |
| Expecting erase to reinstall macOS | Mac restarts to a blank state with no OS | Run Reinstall macOS from the Recovery menu after erasing |
| Not backing up before erasing | All data permanently lost | Verify backups before starting any erase procedure |
| Ignoring Security Options | Old data may be recoverable with software | Use Security Options for sensitive data; one pass suffices for most users |
The Order That Works: Before, During, and After
Before erasing, verify your backup is complete and you can restore from it. Check which chip your Mac uses — click the Apple menu > About This Mac and look at the Chip or Processor line. That tells you whether Erase All Content and Settings is an option or whether you need the Recovery path.
During the erase, if you are using Erase All Content and Settings, follow the on-screen prompts and enter your Apple Account information when asked. If you are using Recovery and Disk Utility, select Macintosh HD, use Erase Volume Group when available, and pick APFS or Mac OS Extended (Journaled). For external drives, enable Show All Devices and select the physical device, not just the volume.
After the erase, if you plan to keep or sell the Mac, quit Disk Utility and choose Reinstall macOS from the Recovery menu. If you are storing the drive or disposing of it, verify the erase worked by checking that Disk Utility shows the drive as empty. For external drives, eject and disconnect them once the erase completes.
The core takeaway from this whole guide is simple: your Mac’s chip determines the method, the format determines compatibility, and backing up first determines whether you lose anything. Get those three right and the rest is a few clicks.
References & Sources
- Apple Support. “Use Disk Utility to Erase an Intel-based Mac.” Official startup-disk erase steps for Intel Macs via macOS Recovery.
- Apple Support Guide. “Erase and Reformat a Storage Device in Disk Utility on Mac.” Complete Disk Utility procedure for internal and external storage devices.
- CubexSoft. “How Do I Completely Erase a Hard Drive on Mac.” Summary of Erase All Content and Settings requirements and Recovery workflow.