I'm using OS X Yosemite - version 10.10.2. I have 1.12 TB fusion drive on my system. Recently I wanted to make a partition on my system, while making the partition on the system using disk utility some error occurred and partition was not created successfully.

The unusable partition of the disk.

The unusable partition

The partition is not available here either. diskutil list

diskutil corestorage list

So, here I'm not able to access the free space partition of my disk. The disk utility is not working with the free space partition. I want to resize the partition and want to have only single partition disk


You have to boot from another device or to Internet Recovery Mode and then use the command line to modify the CoreStorage volume.


  • Backup your data.
  • Detach any external drive (especially your external Time Machine backup drive).
  • Restart to Internet Recovery Mode by pressing alt cmd R at startup.
    The prerequisites are the latest firmware update installed, either ethernet or WLAN (WPA/WPA2) and a router with DHCP activated.
    On a 50 Mbps-line it takes about 4 min (presenting a small animated globe) to boot to a recovery netboot image which usually is loaded from an apple/akamai server.

    I recommend ethernet because it's more reliable. If you are restricted to WIFI and the boot process fails, just restart your Mac until you succeed booting.

    Alternatively you may start from a bootable installer thumb drive (Mavericks or Yosemite) or a thumb drive containing a full system (Mavericks or Yosemite).

Modify CoreStorage:

  • Open in the menubar Utilities/Terminal
  • Enter diskutil cs list
  • Enter diskutil cs resizeStack LVUUID size with LVUUID: UUID of the logical volume and size: the final size of your Macintosh HD
    diskutil cs resizeStack C6AE5E40-1B4F-4AED-BD80-9E71EB6F1352 1000g
    to expand it to 1.0 TB
    diskutil cs resizeStack C6AE5E40-1B4F-4AED-BD80-9E71EB6F1352 0g or
    diskutil cs resizeStack C6AE5E40-1B4F-4AED-BD80-9E71EB6F1352 100%
    to expand it to the full size with magic numbers.

  • Enter exit and quit Terminal.

  • Reboot to your main volume.

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