Create an encrypted volume on a USB drive while keeping other volumes public.

Remarks

• The encrypted volume is only available on Apple devices (iOS, macOS).
• Use a password to decrypt.
• Not accessible on Windows or Android devices.

How ?

1. Plug your USB into a MacBook.
2. Open Disk Utility → Select USB → Erase → Choose "APFS (Encrypted)" → Set password.If there's no APFS option: click View → Show All Devices (top-left) → Select the physical drive (top level), not the volume underneath → click "Erase" → set:
   • Scheme: GUID Partition Map
   • Format: Try "Mac OS Extended (Journaled, Encrypted)" if APFS isn't available

Whenever you plug your USB into macOS, you'll need to enter the password to unlock it.

On iOS devices, use the Files app to open the locked volume.

Split partitions

You can create multiple volumes on the same USB—some encrypted, some not. You can follow these steps even on an already-encrypted USB without causing harm. However, you should back up your data first.

Using Disk Utility → select the USB drive (top level) → Partition → Create different partitions with different options (encrypted or not). For non-encrypted partitions, choose "exFAT" so they can be read by Windows and Android devices.

When you open the USB on Apple devices, all volumes will appear. You can only open encrypted volumes with the password.

On Windows or Android devices, you can only see the non-encrypted volumes.

Change password

Using Disk Utility → select the volume → File → Change Password… → follow the guide.