Home > FileVault 2, Mac administration, Mac OS X > Erasing a FileVault 2-encrypted Volume

Erasing a FileVault 2-encrypted Volume

On occasion, it’s necessary to erase a FileVault 2-encrypted volume. However, Disk Utility won’t let you erase or repartition until you unlock or decrypt.

Screen Shot 2013-06-28 at 11.29.38 PM

Screen Shot 2013-06-28 at 11.29.11 PM

This can be an issue for a malfunctioning FileVault 2-encrypted volume that will not let you either unlock or decrypt. To help with this, the diskutil tool provides a way to quickly delete CoreStorage volumes. This includes the ability to erase encrypted CoreStorage volumes (aka FileVault 2-encrypted volumes) without first decrypting or unlocking them.

To do this, first run the following command:

diskutil cs list

This will give you with a list of the CoreStorage volumes on your system. Unless you have a Fusion drive or multiple encrypted drives, your FileVault 2-encrypted drive should be the only one listed.

In the listing, you will want to select and copy the Logical Volume Group (LVG) alphanumeric UUID for your CoreStorage volume. The LVG should be the first UUID listed and it’s the one we want to delete.

Screen Shot 2013-06-28 at 11.02.40 PM

Next, run the following command:

diskutil cs delete UUID_here

Screen Shot 2013-06-28 at 11.04.29 PM

This will delete your CoreStorage volume and reformat it as an unencrypted HFS+ volume.

Screen Shot 2013-06-28 at 11.04.55 PM

  1. Lee
    June 29, 2013 at 7:37 am

    Great article Richard.

    Would this have any detrimental effect on the drive by “erasing the core storage” vs actually decrypting and formatting?

    • June 29, 2013 at 12:13 pm


      CoreStorage volumes are built by software, so there shouldn’t be any detrimental physical effects to the hard drive.

      In terms of where CoreStorage “lives”, it’s a layer above the disk partitioning, but below the file system used by a particular partition.

  2. January 19, 2014 at 1:28 pm

    Thank you for the information, but it hasn’t help.
    The terminal says: Error: -69691: Couldn’t eject disk

    On Mac OS mavericks.
    Can you help please?

    • Fabian
      January 23, 2014 at 11:07 am

      Hi Cheval,

      I had the same eject problem.
      Try booting in recovery mode (reboot your mac and press and hold “alt”, when you hear the sound and select the recovery partition)
      There you can use diskutility and erase the encrypted partition with it.

      P.S. If you don’t have the recovery partition installed, you can load the recovery system directly from Apple by pressing “Cmd+R” instead of “alt”.

      Good luck

    • Andrew
      August 21, 2015 at 12:10 am


      Don’t forget to use sudo

  3. Vincent
    January 26, 2014 at 11:10 am

    Fabian, ingenious! Rebooting with ‘alt’ worked – then selecting ‘recovery partition’, not my usual HD, then disk utility. I had this problem three times with encrypted time machine disks that became full. They asked for the password but rejected the correct one! Repair ‘not possible’. Formatting did not work (in disk utility or terminal). Deleting the volume group did not work. – Also, this ‘feels’ a lot safer, since I can use disk utility and don’t worry about deleting something I don’t want to delete.


    • May 1, 2014 at 10:07 pm

      Hi Vincent, I have the same problem. This is the second time god my timemachine (encrypted) HDD full and it rejects my password.

      I can’t format, delete, nothing.

      Did you solve this problem in anyway ?

      Thank you.

  4. May 12, 2014 at 9:34 pm

    It’s kind of crazy that you can just delete the contents of the drive with that command, without any confirmation step or password.

  5. Wade
    May 15, 2014 at 8:04 pm

    Don’t know what I would have done without this. Keep up the good work!!

  6. Neif
    October 9, 2014 at 3:11 am

    You are amazing! Thank you. I just moved to a mac and upgraded to OS 10.10 and all hell broke loose. The machine created partition after partition due to bootcamp errors and Yosemite upgrade. And the ice on the cake was my 3TB fusion drive was missing 804GB allocated and hidden from me. Of course coming from windows, live is not as simple as cmd, at least not yet.

    I stupidly reformatted the HDD thinking it would make a difference, and that I would get a chance to redeem myself and merge the drives again, but I was so wrong. After a full day of work, and some searching, I landed on this page…Life Changing. Fixed my problem.

    Thank you from all the newbs to OSX and Terminal.

  7. misho
    October 30, 2014 at 5:42 pm

    Thanks for the help. I had the same problem and followed instructions but now i have 2 seperated drives (i had a fusion drive) one for the ssd and the other for the regular hd. They used to be one as a fusion drive. How to combine them again?

    • October 31, 2014 at 4:44 pm

      You can’t do this on a fusion drive. This is only used for non-fusion drive setups.

  8. Chris
    November 12, 2014 at 9:28 pm

    Thank you so much Richard,
    I was almost going crazy with that partition hidden/crashed by filevault. Apple support couldn’t help me, no German board could, but you did!
    Thanks again & kindest regards from Germany

  9. Bob Kretz
    November 15, 2014 at 2:38 pm

    I do not have enough words for how helpful this was for me. It has been a problem for days, with visits to dozens of websites, and over an hour on the phone with a senior tech guy at OWC. Thank you, thank you!

  10. Bruce Guidotti
    December 30, 2014 at 9:16 pm

    Rich, I’ve noticed that this procedure also deletes the Recovery Partition.
    Is there any way around that?

  11. RJ
    January 14, 2015 at 4:11 am

    Works perfectly thanks

  12. hjyssg47
    February 16, 2015 at 11:52 am

    Thank you very much. This is very helpful.

  13. Mindkido
    March 12, 2015 at 12:14 am

    thanks for the great procedure. I just bought my macbook pro retina and also activated filevault. The next day I tried to restore my system using Time Machine but it all screwed up because the drive got locked and no way to unlock it. I called Apple and they tranferred me to higher support level and finally told me to go to Apple store for repair. I couldn’t wait so I searched on google and found this procedure. I finally deleted the drive using the diskutil command like you said and successfully reinstall the OSX. thanks so much. Filevault sucks! it’s recommended not to use filevault disk encryption.

  14. Nick
    March 14, 2015 at 1:29 am

    Worked brilliantly. Thank you!

  15. lodger
    March 22, 2015 at 5:25 pm

    Thank you so much! I was this close to giving up on that drive when it started going back because of a FileVault error. At first it asked for the password, which I had, but it wouldn’t stop accessing the disk. Discovered that somehow FileVault encryption had been “paused” and it was just kind of hanging there. Your workaround enabled me to wipe it and start over. This time I won’t be enabling FV. Thank you!!!!

  16. theorist
    May 31, 2015 at 12:02 am

    I have a separate, but related, question Suppose you have an external HD you need to send back to the manufacturer for replacement. If the drive is encrypted, from a security viewpoint, is there any need to erase it? I.e., does encryption obviate the need to erase, at least when it comes to protecting your personal info.?

  17. Carsten Denmark
    June 25, 2015 at 6:04 pm

    Works very great

  18. nykodj
    November 7, 2015 at 5:47 pm

    thx…works great…..

  19. November 25, 2015 at 8:07 pm

    Thank you

  20. jose
    December 14, 2015 at 10:20 pm

    Started CoreStorage operation
    Ejecting Logical Volumes
    The volume “Macintosh HD” on disk1 couldn’t be unmounted
    Error: -69888: Couldn’t unmount disk

  21. April 28, 2016 at 3:12 am

    Saved the day! I booted into the Recovery partition, followed the above, and now I’m waiting for the download of OS. Totally worth the wait. Nothing as frustrating as FileVault.

    Thanks for the post!

  22. May 9, 2016 at 1:53 am

    i get the message ownership of the affected disk is required:/

  23. al
    August 8, 2016 at 5:24 pm

    Thank you! I’m trying quite desperately to erase a filevault encrypted SD card without success.
    $ sudo diskutil cs delete LVG_ID_HERE
    Started CoreStorage operation
    Unmounting Logical Volumes
    Ejecting Logical Volumes
    Destroying Logical Volume Group
    Erasing disk3s2
    Initialized /dev/rdisk3s2 as a 118 GB case-insensitive HFS Plus volume with a 16384k journal
    Mounting disk
    Could not mount disk3s2 with name (null) after erase
    Finished CoreStorage operation

    any idea?
    running El Capital 10.11.6

    • Diego
      September 17, 2016 at 4:22 pm

      Mee too .. same problem

  24. jon
    September 28, 2016 at 12:34 am

    Awesome! Worked on the first try!!!! Thanks so much for this simple and straightforward explanation!

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