Removing Core Storage Volumes and Volume Groups

If repartitioning a disk with DiskUtility is not possible using the command line and you see an error like the following :

  # diskutil eraseDisk jhfs+ Macintosh\ HD  /dev/disk2
  Unable to begin erase operation: Placing a partition map on a 
  Core Storage logical volume is not supported (-69671)

The information on this page will assist with removal of Core Storage logical volume.

Bear in mind that any data on that volume group and its volumes will be erased; proceed with caution.

The Following URL has detailed information : http://macs.about.com/od/diyguidesprojects/ss/Split-Your-Fusion-Drive-Apart.htm

This page summaries the commands required to remove the volume and the volume group.

 # diskutil cs list
 CoreStorage logical volume groups (1 found)
  |
  +-- Logical Volume Group 8F5224E9-ADB9-4AD6-9617-D28E34DC9043
      =========================================================
      Name:         Macintosh HD
      Status:       Online
      Size:         60607803392 B (60.6 GB)
      Free Space:   18948096 B (18.9 MB)
      |
      +-< Physical Volume F4504240-8EA0-4E6E-A23C-971787CEED74
      |   ----------------------------------------------------
      |   Index:    0
      |   Disk:     disk1s2
      |   Status:   Online
      |   Size:     60607803392 B (60.6 GB)
      |
      +-> Logical Volume Family 7E535D2D-6A3C-455F-A1BE-D66D247C3815
          ----------------------------------------------------------
          Encryption Status:       Unlocked
          Encryption Type:         None
          Conversion Status:       NoConversion
          Conversion Direction:    -none-
          Has Encrypted Extents:   No
          Fully Secure:            No
          Passphrase Required:     No
          |
          +-> Logical Volume 7271A636-A6C9-418E-BEF5-C3C71FFC25BE
              ---------------------------------------------------
              Disk:                  disk2
              Status:                Online
              Size (Total):          60236533760 B (60.2 GB)
              Conversion Progress:   -none-
              Revertible:            Yes (no decryption required)
              LV Name:               Untitled
              Volume Name:           Untitled
              Content Hint:          Apple_HFS

Basically, you will then delete Logical Volume with the following command (replace the UUID with the appropriate UUID of the volume you are attempting to delete :

  # diskutil cs deleteVolume 7271A636-A6C9-418E-BEF5-C3C71FFC25BE
  The Core Storage Logical Volume UUID is 7271A636-A6C9-418E-BEF5-C3C71FFC25BE
  Started CoreStorage operation on disk2 Untitled
  Unmounting disk2
  Removing Logical Volume from Logical Volume Group
  Finished CoreStorage operation on disk2 Untitled

Finally, you will delete Logical Volume Group with the following command (replace the UUID with the appropriate UUID of the volume group you are attempting to delete :

  # diskutil cs delete 8F5224E9-ADB9-4AD6-9617-D28E34DC9043
  The Core Storage Logical Volume Group UUID is 8F5224E9-ADB9-4AD6-9617-D28E34DC9043
  Started CoreStorage operation
  Destroying Logical Volume Group
  Erasing disk1s2
  Initialized /dev/rdisk1s2 as a 56 GB case-insensitive HFS Plus volume with a 8192k journal
  Mounting disk
  Finished CoreStorage operation