I can use Disk Utility to create an encrypted partition, intended for Time Machine backups. I would choose the Mac OS X Extended (Journaled, Encrypted) format.

However is there also away to achieve the same from the command line, using the diskutil or gpt command, or something else perhaps?

I know how to manually create partitions with either, I just don't know how to get the exact combination of Mac OS X Extended (Journaled, Encrypted) as the Disk Utility App does.


1 Answer 1


Below (in the steps 1-5) I assume you already formatted some device as JHFS+ volume with an arbitrary name (in my example I use TMBackup). If you have an unformatted/unpartitioned disk, you have to partition & format it to JHFS+ first:

$: diskutil list
$: diskutil partitionDisk diskX GPT jhfs+ Name 0

or (if the disk is already GPT-partitioned with one volume):

$: diskutil eraseDisk JHFS+ Name /dev/diskXsY

The content of diskX(sY) will be deleted.

  1. Get the devices list:

    $: diskutil list


    /dev/disk1 (internal, physical):
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *1.1 TB     disk1
       1:                        EFI EFI                     209.7 MB   disk1s1
       2:                  Apple_HFS TMBackup                1.1 TB     disk1s2
  2. Choose the future backup drive partition and convert it to CoreStorage:

    $: diskutil cs convert diskXsY

    Example result:

    $: diskutil cs convert disk1s2
    Started CoreStorage operation on disk1s2 TMBackup
    Resizing disk to fit Core Storage headers
    Creating Core Storage Logical Volume Group
    Reviewing boot support loaders
    Attempting to unmount disk1s2
    Switching disk1s2 to Core Storage
    Waiting for Logical Volume to appear
    Mounting Logical Volume
    Core Storage LVG UUID: 586B5316-C702-4704-B8B9-D5F063AB1F84
    Core Storage PV UUID: 17373D1A-FCBD-4915-8699-3DA174B59BB7
    Core Storage LV UUID: AE765219-2012-4876-91DD-FE128DC8CA6C
    Core Storage disk: disk3
    Finished CoreStorage operation on disk1s2 TMBackup
  3. Encrypt the logical volume (LV)

    $: diskutil cs encryptVolume $UUID(LV)


    $: diskutil cs encryptVolume AE765219-2012-4876-91DD-FE128DC8CA6C
    New passphrase for existing volume:
    Confirm new passphrase:
    The Core Storage Logical Volume UUID is AE765219-2012-4876-91DD-FE128DC8CA6C
    Started CoreStorage operation on disk3 TMBackup
    Reviewing boot support loaders
    Scheduling encryption of Core Storage Logical Volume
    Core Storage LV UUID: AE765219-2012-4876-91DD-FE128DC8CA6C
    Finished CoreStorage operation on disk3 TMBackup
  4. Set destination device for Time Machine backups:

    $: sudo tmutil setdestination mountpoint


    $: sudo tmutil setdestination /Volumes/TMBackup 
  5. Enable Time Machine

    $: sudo tmutil enable
  • Awesome, was not aware of diskutil's cs command before! And also being able to appoint it as a Time Machine volume from the command line using tmutil is even better. Thanks a lot!
    – RocketNuts
    Feb 6, 2020 at 20:29

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