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By default, removable media (disks) on macOS such as removable disks and memory cards are not encrypted. If removable media is lost or stolen, someone else can access its data. To keep your data secure on removable media, you will need to encrypt the information on it.
Warning: Encrypting removable media will convert the disk format to APFS format. APFS format is supported by macOS 10.13 (High Sierra) and later. Macs running older macOS versions will not be able to read APFS-formatted removable media.
1. In the macOS Finder, right-click or control-click on the item you want to encrypt.
2. Choose Encrypt.
3. Choose a password for the disk and click Encrypt Disk.
Do not lose the password. Data on the encrypted disk cannot be accessed without it. Encrypting the disk can take some time, depending on the amount of data on the disk. You can continue to use the disk while it is being encrypted.
4. When you connect an encrypted disk to a computer, you’ll be prompted for the password. Data on the encrypted disk cannot be accessed without the password.
Frequently Asked Questions
1. Can my encrypted disk be used on any Mac or only on the Mac that encrypted it?
Your encrypted disk can be used by any Mac as long as the user knows the password.
2. The Encrypt option doesn’t show up in the menu.
Some things to check:
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Is your computer running macOS 10.13 or higher? If not, it cannot encrypt removable media.
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Is your removable media formatted as APFS or Mac OS Extended? Right-click or control click and choose Get Info to determine the disk format. If it is a different format, then it needs to be reformatted (erased) as APFS or Mac OS Extended before it can be encrypted.
3. Will encrypting a disk cause the existing data on the disk to be erased?
If your disk is formatted as Mac OS Extended or APFS, encrypting the disk will not erase the existing data. Disks formatted as Mac OS Extended will be converted to APFS.
If your disk is not formatted as Mac OS Extended or APFS, it will need to be formatted (erased) using Disk Utility before it can be encrypted. Formatting a disk WILL erase the existing data.
4. I no longer want my disk to be encrypted. How do I remove encryption permanently?
To remove encryption, right-click or control click on the disk and then choose Decrypt.
