I wanted to create a partition on my iMac for Windows to be able to play Windows games. I have used Disk Utility to create a 20GB partition on my 1,12TB Fusion drive. This caused a problem on my system.

The partition was not created, but my main Macintosh HD drive has all of a sudden 1,09 instead of the 1,12TB available.

Current HD size

Fusion drive size

It seems that my ghost partition has been created, but it is unfindable. When I try to create a new partition I get a direct error telling me that my coreStorage volume has a wrong size, so i'm not able to create a partition.

Partitioning windows enter image description here

I have searched the web and found some terminal scripts to resize the size of my HD, but this did not work. I have done the following steps:

Check the real size of my drive and partitions through terminal diskutil list

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Macintosh HD            121.0 GB   disk0s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk0s3

/dev/disk1 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:          Apple_CoreStorage Macintosh HD            999.3 GB   disk1s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3

/dev/disk2 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           +1.1 TB     disk2
                                 Logical Volume on disk0s2, disk1s2
                                 Unlocked Encrypted Fusion Drive

Check more information about coreStorage through diskutil corestorage list

CoreStorage logical volume groups (1 found)
+-- Logical Volume Group BF423173-90A8-41A7-8DE7-57D77312FCFC
    Name:         Macintosh HD
    Status:       Online
    Size:         1120333516800 B (1.1 TB)
    Free Space:   19350335488 B (19.4 GB)
    +-< Physical Volume 6CBD9709-B121-44E7-9F69-F9C826667DAA
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     120988852224 B (121.0 GB)
    +-< Physical Volume 817A970A-6E03-4522-A4C6-FBBA0CB26C71
    |   ----------------------------------------------------
    |   Index:    1
    |   Disk:     disk1s2
    |   Status:   Online
    |   Size:     999344664576 B (999.3 GB)
    +-> Logical Volume Family FE8B314E-1766-4D4A-BCD1-B5ECC9AAF9AD
        Encryption Type:         AES-XTS
        Encryption Status:       Unlocked
        Conversion Status:       Complete
        High Level Queries:      Fully Secure
        |                        Passphrase Required
        |                        Accepts New Users
        |                        Has Visible Users
        |                        Has Volume Key
        +-> Logical Volume 4DC798D4-AF57-4F51-A5D2-4B33DE10B887
            Disk:                  disk2
            Status:                Online
            Size (Total):          1092475813888 B (1.1 TB)
            Revertible:            No
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS
            LVG Type:              Fusion, Sparse

Try to resize the volume of my drive through diskutil coreStorage resizeVolume 4DC798D4-AF57-4F51-A5D2-4B33DE10B887 1120333516800b

diskutil coreStorage resizeVolume 4DC798D4-AF57-4F51-A5D2-4B33DE10B887 1120333516800b
The Core Storage Logical Volume UUID is 4DC798D4-AF57-4F51-A5D2-4B33DE10B887
Started CoreStorage operation
Error: -69674: The provided Core Storage logical volume has an incorrect size; you should run whole-disk repair

I have check the drives with "First aid" in Disk utility and everything came back fine, so I think it is only a storage amount issue.

Does anyone know how to solve this? and make sure I can restore the full amount of storage on my HD in order to create a new windows partition?


System: macOS High Sierra 10.13.6 ~ 21.5" iMac Late 2012 ~ 2.7 GHz Intel Core i5

  • The specified logical Core Storage-volume has incorrect size ! You must restore the entire disk.
    – Ruskes
    Commented Oct 30, 2018 at 19:05
  • Thanks Buscar, Could you explain a bit more about how I do this? And does that mean that I will lose any data?
    – Jeroen
    Commented Oct 30, 2018 at 19:19
  • support.apple.com/guide/disk-utility/repair-a-disk-dskutl1040/… make sure you select entire volume no just a portion. And yes, you should back up before. Also since you have a Fusion drive read the part on it.
    – Ruskes
    Commented Oct 30, 2018 at 19:33
  • I have tried this as well and get the following message: "invalid disk operation failed"
    – Jeroen
    Commented Oct 30, 2018 at 20:19
  • hope you have recent back up.
    – Ruskes
    Commented Oct 30, 2018 at 20:23

1 Answer 1


To run a whole-disk repair, you need to do it from the command-line: diskutil repairDisk /dev/disk1

Be sure to use the correct disk identifier (in this case it was /dev/disk1); in diskutil list you're looking for a disk marked physical in order to specific the entire physical disk (i.e. not a logical disk). If you incorrectly use a logical disk identifier instead, you will get the error: You cannot specify a CoreStorage logical volume (and a logical volume should not have a partition map)

  • In my case it was disk0 and it warned that the disk could be erased. I continued and luckily it survived. Then I could do the partition using DiskUtility GUI.
    – kmchmk
    Commented Aug 14, 2021 at 18:20

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