OK, I'm running El Capitan OS X 10.11. The Apple app "Disk Utility" is useless to create encryption, as it typically returns
Operation Failed with status 28
So the fix is to use a little terminal magic. After adding your USB drive to the Mac, run terminal
At the command-line prompt, enter:
diskutil list
You will see your main (internal) disk listed, as well as your USB:
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.3 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_CoreStorage Macintosh HD 499.4 GB disk0s2
3: Apple_Boot Recovery HD 650.1 MB disk0s3
/dev/disk1 (internal, virtual):
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS Macintosh HD +499.1 GB disk1
Logical Volume on disk0s2
B0B7A5AA-7D8D-41E3-8565-82E4E1D685D5
Unlocked Encrypted
/dev/disk2 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *31.5 GB disk2
1: Windows_FAT_32 KINGSTON 31.5 GB disk2s1
You can spot your external drive by its size -- mine is 32 GB, which, after overhead is around 31.5. In other words, its name is KINGSTON at drive identifier disk2s1.
Now, using your USB drive's device identifier in place of disk2s1, pick a suitable name for your new drive. I like thing2:
diskutil eraseDisk JHFS+ thing2 /dev/disk2
About 30 seconds of progress later, you should get:
Finished erase on disk2
Now, open a Finder window, and right click your newly named disk. Pick the option encrypt . In my case, the USB 3.0 encryption took about 12 minutes of effort for 32 GB (45MB/s write). You will know you are done, when the drive activity light goes out.
up for one answer above, plus make sure that the adapter you're using is the right adapter for running the external hard drive's operating system. I had a 2015 MacBook Pro and I was running kali linux on an external hard drive. I was forced to buy the 2017 version since my dad needed a new computer and he wanted the 2015 MacBook I had. I mindlessly just picked out a USB-C to USB adapter, and that adapter worked for reading and transferring files from different hard drives, but when I try booting the kali linux hard drive, it would ask "which hard drive to boot" after pressing the option key, but it would end up having a black screen when I chose the kali. I almost deleted the kali linux operating system I had, and all the files in it (repeat/repartition drive, etc) but a light bulb came to my head and prompted me to check the box of that stupid adapter I bought...sure enough, it was only a USB-C to Type A USB. This may not be the same case for you, but my problem was solved when I bought a different adapter for the USB-C connection for the 2017 Mac.
Best Answer
This is an example workflow to encrypt an USB thumbdrive with HSF+ (Journaled) with
diskutil
using the command line.Assuming you start with a MS-DOS formatted USB stick.
Step 1: List all currently mounted disks
diskutil list
:You see the disk
MYSTORAGE
has the identifierdisk2s1
and isDOS_FAT_32
formatted.Step 2: Now format the disk
disk2
as HSF+ (Journaled):The name of the disk will be "New Storage". At this time it is not yet encrypted. Look at the list of disks
diskutil list
:Step 3: Now you see the "New Storage" partition with identifier
disk2s2
. Encrypt this partition using:Enter the passphrase when prompted.
If you list the disks now, you also see the encrypted logical volume
diskutil list
:If you skip step 3, you can also encrypt the disk using Finder:
Just right-click on the drive and select "Encrypt drive-name".