The Data Sanitization Vector
Before you sell your old Mac, trade it in, or hand it down to a family member, you must absolutely guarantee that every single photograph, password, and financial document is completely eradicated from the physical storage drive. Simply dragging files to the Trash and emptying it does not actually delete the data; it merely tells the operating system that the space is available to be overwritten. Anyone with basic data recovery software can retrieve those “deleted” files in minutes.
How to Erase a Hard Drive
You must use the core macOS Disk Utility to perform a cryptographic wipe, destroying the encryption keys and rendering the data permanently inaccessible.
1. If you are wiping your primary internal drive, you must first completely shut down the Mac.
2. For Apple Silicon (M1/M2/M3) Macs: Press and hold the power button until you see “Loading startup options.” Click Options, then Continue.
For Intel Macs: Press the power button, then immediately press and hold Command (⌘) + R until you see the Apple logo.
3. You are now in macOS Recovery Mode. If prompted, select a user and enter the administrator password.
4. From the main utilities window, select Disk Utility and click Continue.
5. In the left-hand sidebar, select your primary hard drive (usually named “Macintosh HD”).
6. Look at the top toolbar and click the Erase button.
7. A dialogue box will appear.
* Name: Leave it as “Macintosh HD”.
* Format: Ensure this is set to APFS (Apple File System).
8. Click the Erase Volume Group button (or just Erase on older systems).
The Disk Utility will instantly obliterate the cryptographic keys associated with the volume. Because modern Macs encrypt data by default, destroying the keys mathematically guarantees that the underlying data can never be reconstructed, regardless of the recovery tools employed.