I have created new partition by selecting free space option and now I can't merge it or recreate it.

I have tried to use iPartition to create a new partition on free space but it said I have no permission.

How can I fix it?

Disk Utility

  • do you want one big or two separate partitions? If you want two partitions i will add the necessary steps to my answer
    – klanomath
    Nov 8 '14 at 13:37
  • I found this problem has a much easier solution than "expanding core storage volume". 1) use "diskutil list" to find out the UUID of the logical volume. 2) use "diskutil cs revert <LVUUID>" to get rid of core storage & logical volume (which, IMO, is an incredibly stupid design). 3) reboot. Then "Disk Utility" would work as expected.
    – user416983
    Dec 11 '15 at 16:26

Your volume Macintosh HD is a Core Storage Logical Volume and part of a Core Storage volume group and thus can't be modified by iPartition or Disk Utility.

You have to boot from an external disk, a thumb drive or in the Internet Recovery Mode to be able to modify the volume with some Terminal commands.

The following diskutil cs resizeStack command is vastly undocumented and as such potentially destructive.

Please backup your Mac OS X before proceeding.

A 2nd computer or an iPhone with the stackexchange credentials to enter the site or the chat is usefull.

Please start Terminal from /Applications/Utilities and enter diskutil cs list to get an impression.

Example output of diskutil cs list

$ diskutil cs list
CoreStorage logical volume groups (1 found)
+-- Logical Volume Group 08436957-C5CD-4DC6-B9FA-05B51A3EEFC8
    Name:         Macintosh HD
    Status:       Online
    Size:         86908663234 B (80.94 GB)
    Free Space:   35364864 B (35.4 MB)
    +-< Physical Volume FFC67A8D-65A8-415E-A594-D7A6BED71844
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     86908663234 B (80.94 GB)
    +-> Logical Volume Family 56C0E988-502B-43D5-90DD-EFBE58143896
        Encryption Status:       Unlocked
        Encryption Type:         None
        Conversion Status:       NoConversion
        Conversion Direction:    -none-
        Has Encrypted Extents:   No
        Fully Secure:            No
        Passphrase Required:     No
        +-> Logical Volume 4F26F5C3-8D94-419F-AFF1-B652E9DCDEF4
            Disk:                  disk1
            Status:                Online
            Size (Total):          86479166504 B (80.54 GB)
            Conversion Progress:   -none-
            Revertible:            No
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS

Your Mac OS X partition (Macintosh HD) visible on the desktop is equivalent to the Logical Volume F26F5C3-8D94-419F-AFF1-B652E9DCDEF4.

Reclaim the free space:

After resizing some dozens of disks with diskutil cs resizeStack LVUUID I never had a problem with the Recovery HD. So step 1-6 may be considered dispensable and you may directly start with step 7.

  1. First you have to backup your Recovery HD: Start Terminal.app and enter
    defaults write com.apple.DiskUtility DUDebugMenuEnabled 1 press enter and quit Terminal.app
  2. Start Disk Utility and enable 'Show every Partition' in the Debug menu After a few seconds all partitions should be visible
  3. Choose Recovery HD on the left side and mount the partition Recovery HD


  4. Verify the disk


  5. Create a disk image of Recovery HD and save it read-only externally


  6. Check the disk image for restore


  7. Detach all external drives

  8. Restart into Internet Recovery Mode by pressing altcmdR
    or a bootable Mavericks or Yosemite Thumb Drive (full system or install).

  9. start Terminal from the menubar/utilities
  10. enter following command at the Terminal prompt:

    diskutil cs list

  11. Copy the Logical Volume (LV) alphanumeric UUID of your CoreStorage volume. The LVUUID should be the fourth listed. In the above example the alphanumeric is:
  12. Run the following command:

    diskutil cs resizeStack LVUUID partsize  

    According to the number found above it would be:

    diskutil cs resizeStack F26F5C3-8D94-419F-AFF1-B652E9DCDEF4 100%

    If you get an error ("A percentage value (100%) cannot be specified for this operation.") use this instead:

    diskutil cs resizeStack F26F5C3-8D94-419F-AFF1-B652E9DCDEF4 0g

    This will hopefully expand your CoreStorage volume to allmost full 120 GB. Depending on your disk this will take several seconds (SSD) or minutes (HDD). After a successful resize check with diskutil list if the Recovery HD still exists.

  13. Quit Terminal.app and start Disk Utility and verify the expanded volume.
  14. Reboot to Recovery HD and your main drive. Delete the disk image created in step 5 if everything works as expected
  • cs resizeStack with 100% doesn't work for me, I get an error saying A percentage value (100%) cannot be specified for this operation.
    – zenith
    Apr 6 '15 at 17:00
  • @zenith Try diskutil cs resizeStack ... 0g instead. 0g is a magic number
    – klanomath
    Apr 6 '15 at 17:05
  • @zenith better use the linked and accepted answer.
    – klanomath
    Apr 6 '15 at 17:07
  • edit: El Capitan: diskutil you need to use just 0, not 0g, as it was on Yosemite. Sep 6 '15 at 14:31
  • @DaliborFilus Thanx for the hint. I will add that after El Capitan has grown out of its beta existence
    – klanomath
    Sep 6 '15 at 14:37

Back up all of your data beforehand. Note this procedure may not work if the volume is encrypted. You may need to either decrypt the volume or unlock it with the passphrase/recovery key in order to resize it. See Undocumented CoreStorage Commands for more information.

1) Open Terminal.

2) Enter the following command to find the UUID of the Logical Volume. Make sure you select the correct UUID. Copy it.

diskutil cs list 

3) Enter the following command (replacing lvUUID with the copied lvUUID) to resize the logical volume back to it's full capacity. Enter your password when prompted.

sudo diskutil cs resizeVolume lvUUID %100

4) Once it completes, exit terminal. Open up System Preferences > Startup Disk and re-select the volume to Bless it again as the boot volume.


It's a Core Storage volume [Logical Volume Group] - which I'd guess is either a Fusion Drive or FileVault encrypted drive.

Either way, iPartition cannot handle it.

Judging by the number of people who've broken a Fusion drive by trying to 'clean up' the partitioning, it's really something Apple should prevent the user doing...

The best suggestion I've seen for recovery is to delete the drives' UUIDs & then let Disk Utility rebuild it from the ground up. All data is lost, so a full backup is essential.

Have a look at Split Your Fusion Drive Apart then Setting Up a Fusion Drive on Your Current Mac.

[I'd précis here, but there are 8 pages of instructions]

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