How to Encrypt an External Drive on macOS

Secure your external storage by enabling XTS-AES 128-bit or 256-bit encryption. Follow these steps to password-protect your drive using Disk Utility.

1. Back up existing data. Encryption requires reformatting the drive, which will erase all existing files. Copy all data currently on the drive to a secure secondary location before proceeding.
2. Open Disk Utility. Press Command + Space to open Spotlight Search. Type 'Disk Utility' and press Return to launch the application.
3. Locate the external drive. Click the View button in the top-left toolbar and select 'Show All Devices.' Select the root level of your external drive in the sidebar to ensure you are formatting the entire disk.
4. Initiate the erase process. Click the Erase button in the toolbar. A dialog box will appear requiring you to define the volume properties.
5. Set encryption parameters. Enter a name for your drive, select 'GUID Partition Map' as the Scheme, and choose 'APFS (Encrypted)' as the format. You will be prompted to enter and verify a strong password; do not lose this, as there is no password recovery option for encrypted volumes.
6. Finalize encryption. Click Erase. macOS will partition the drive, apply the encryption keys, and mount the volume. Once the progress bar finishes, click Done.