The internal disk of my Mac book pro is partitioned as follows:

% diskutil list
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS mainHD                  249.7 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:          Apple_CoreStorage                         249.1 GB   disk0s4
   5:                 Apple_Boot Recovery HD             650.0 MB   disk0s5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS oldHD                  *248.7 GB   disk1

% diskutil cs list
CoreStorage logical volume groups (1 found)
+-- Logical Volume Group C2BDDBCA-73CF-473C-B9DA-E5682EF29610
    Name:         Macintosh HD 2
    Status:       Online
    Size:         249059012608 B (249.1 GB)
    Free Space:   35708928 B (35.7 MB)
    +-< Physical Volume CA1B7050-0A3D-4FFD-ADC2-AE42B45BEB9C
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s4
    |   Status:   Online
    |   Size:     249059012608 B (249.1 GB)
    +-> Logical Volume Family 4CBD3D40-147F-4B2D-A997-975E00295101
        Encryption Status:       Unlocked
        Encryption Type:         None
        Conversion Status:       NoConversion
        Conversion Direction:    -none-
        Has Encrypted Extents:   No
        Fully Secure:            No
        Passphrase Required:     No
        +-> Logical Volume B3E1FCD6-ACAB-4152-AEB5-71F41C329C17
            Disk:                  disk1
            Status:                Online
            Size (Total):          248687755264 B (248.7 GB)
            Conversion Progress:   -none-
            Revertible:            Yes (no decryption required)
            LV Name:               oldHD
            Volume Name:           oldHD
            Content Hint:          Apple_HFS

The operating system (os x 10.9.5) and all my files are in the mainHD, where I'm running out of space. I would like to delete the oldHD so that I can increase the size of mainHD.

When I try to delete oldHD via the graphical disk utility I get an Alert (null) box where I can select cancel or remove, if I click on remove nothing happens and in the log I see:

: Preparing to remove partition from disk: “APPLE SSD SM512E Media”
: Could not unmount partition to be deleted.

How can I get oldHD deleted and mainHD resized?


To delete CoreStorage volumes you have to use the CLI:

  • please backup your volume "mainHD"
  • boot to Internet Recovery Mode (hit altcmdR immediately after the start-up chime)
  • open Disk Utility and check/repair mainHD
  • quit Disk Utility , open in the menubar Utilities/Terminal.app and enter diskutil cs deleteVolume LVUUID to delete the Logical Volume
    in your case: diskutil cs deleteVolume B3E1FCD6-ACAB-4152-AEB5-71F41C329C17

  • and then
    diskutil cs delete LVGUUID to delete the Logical Volume Group
    in your case: diskutil cs delete C2BDDBCA-73CF-473C-B9DA-E5682EF29610. Your LGV will be converted to a simple, empty volume with the name "Untitled".

  • enter diskutil list and sudo gpt -r -vvv show -l /dev/disk0
    result of the latter (start blocks and block sizes differ because the example disk is half as big as yours & some parts of the output are omitted):

             40       409600      1  GPT part - "EFI System Partition"
         409640    244763224      2  GPT part - "mainHD"
      245172864      1269536      3  GPT part - "Recovery HD"
      246442400    242522776      4  GPT part - "Untitled"
      488965176      1269536      5  GPT part - "Recovery HD"
  • enter diskutil unmountDisk /dev/disk0
  • then remove any partition except those with index 1 and 2 (EFI and mainHD) with sudo gpt remove -i IndexNumber disk0
  • enter diskutil resizeVolume disk0s2 0b to expand it to the full size.
  • enter exit and quit Terminal
  • open Disk Utility, check/repair mainHD again and quit afterwards
  • reboot to main HD
  • rebuild Recovery HD with Recovery Partition Creator 3.8 or by just reinstalling Mavericks 10.9.5 (don't use 10.9.4 or earlier!). Your data and apps will be preserved.
| improve this answer | |
  • Thanks it worked, I did the deletion with the command line, and the resizing with the graphic utility. – Don Giulio Feb 17 '15 at 17:33
  • @user72464 ok and what did you do with your second Recovery HD? – klanomath Feb 17 '15 at 17:38
  • it's not there any more, it must be gone when I deleted the Logical volume – Don Giulio Feb 17 '15 at 22:15

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