9

I seem to have badly botched a Boot Camp installation of Windows 8.1. I used Boot Camp Assistant to create a 200 GB BOOTCAMP partition on my 1 TB Fusion Drive. I then rebooted and failed to install Windows because I did not know at the time that having my external backup drive plugged in would cause the Windows installer to not work. From the Windows setup partition tool, I tried formatting the BOOTCAMP partition. That did not help, so I tried deleting it and creating a new partition in its place. That did not work either, which leads me to where I am now.

I have a ~800 GB Macintosh HD partition and a 200 GB Free Space partition I need to get rid of to be able to give Boot Camp another go. These are depicted below.

Macintosh HD partition I would like to extend Free Space partition I need to eliminate

Notice in the above screenshots, there seems to be no way to change the sizes of those partitions.

When I try to use Boot Camp Assistant now, I get the following error message:

The startup disk cannot be partitioned or restored to a single partition. The startup disk must be formatted as a single Mac OS Extended (Journaled) volume or already partitioned by Boot Camp Assistant for installing Windows.

Boot Camp Assistant failing because I don't have a single partition

Note: I have attempted (twice) to reboot and use the Disk Utility from the recovery menu, but I get the same results.

  • I considered using a bootable GParted since it will be able to access/delete all the partitions Mac OS can't see. The problem, then, is that I don't know the original partition configuration of the fusion drive I need to restore. I don't want to repartition the wrong way and somehow screw up the fusion drive's performance. – Eric Jul 17 '14 at 14:14
5

There is no need to delete the CoreStorage Logical Volume Group. Just resize it:

  1. Have a backup!

  2. Reboot into Internet Recovery Mode (hold Option-Command-R) as the machine is restarting). You'll eventually be presented with a Max OS X Utilities window.

    OS X Recovery Mode

  3. In the menu bar along the top of the screen, click Utilities -> Terminal.

    Utilities, Terminal

  4. At the prompt, enter diskutil cs list and you should get output similar to the following.

    CoreStorage logical volume groups (1 found)
    |
    +-- Logical Volume Group 9B4FB14F-DA7D-46EF-BBB9-FD99166C1E2F
        =========================================================
        Name:         Macintosh HD
        Status:       Online
        Size:         920186970112 B (920.2 GB)
        Free Space:   49152 B (49.2 KB)
    |
    +-< Physical Volume DE3C1DD4-3EA5-4484-AE40-C8BD60AD5F75
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     120988852224 B (121.0 GB)
    |
    +-< Physical Volume E1C56E99-3ED2-437F-AED0-A454FCC4E983
    |   ----------------------------------------------------
    |   Index:    1
    |   Disk:     disk1s2
    |   Status:   Online
    |   Size:     799198117888 B (799.2 GB)
    |
    +-> Logical Volume Family D824D426-8315-405A-A7CD-5B62E549FBAE
        ----------------------------------------------------------
        Encryption Status:       Unlocked
        Encryption Type:         None
        Conversion Status:       NoConversion
        Conversion Direction:    -none-
        Has Encrypted Extents:   No
        Fully Secure:            No
        Passphrase Required:     No
        |
        +-> Logical Volume AC1A071B-63D0-488F-AFFF-D296E446FE6B
            ---------------------------------------------------
            Disk:                  disk2
            Status:                Online
            Size (Total):          914000052224 B (914.0 GB)
            Conversion Progress:   -none-
            Revertible:            No
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS`
    
  5. Copy the Logical Volume (LV) alphanumeric UUID of your CoreStorage volume. The LVUUID should be the fourth (the fifth if you have a Fusion Drive) listed. In the above example the alphanumeric is:
    AC1A071B-63D0-488F-AFFF-D296E446FE6B

  6. Run the following command:

    diskutil cs resizeStack LVUUID partsize  
    

    According to the number found above it would be:

    diskutil cs resizeStack AC1A071B-63D0-488F-AFFF-D296E446FE6B 0g  
    

    This will expand your CoreStorage volume to full 1.24 TB

  7. Quit Terminal.app and start Disk Utility and verify the expanded volume.
4

I contacted Apple Support and got this solution directly from them. It's a simple fix, actually.

WARNING: ONLY FOLLOW THESE INSTRUCTIONS IF YOU HAVE EITHER:

  1. Backed up the precious contents of your drive, or...
  2. After a thoughtful and deliberate count to 10, decided you couldn't care less about the worthless contents of your drive.

Reboot into Recovery Mode (hold Cmd-R as the machine is restarting). You'll eventually be presented with a Max OS X Utilities window.

OS X Recovery Mode

In the menu bar along the top of the screen, click Utilities -> Terminal.

Utilities, Terminal

At the prompt, enter diskutil cs list and you should get output similar to the following.

CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group 9B4FB14F-DA7D-46EF-BBB9-FD99166C1E2F
    =========================================================
    Name:         Macintosh HD
    Status:       Online
    Size:         920186970112 B (920.2 GB)
    Free Space:   49152 B (49.2 KB)
    |
    +-< Physical Volume DE3C1DD4-3EA5-4484-AE40-C8BD60AD5F75
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     120988852224 B (121.0 GB)
    |
    +-< Physical Volume E1C56E99-3ED2-437F-AED0-A454FCC4E983
    |   ----------------------------------------------------
    |   Index:    1
    |   Disk:     disk1s2
    |   Status:   Online
    |   Size:     799198117888 B (799.2 GB)
    |
    +-> Logical Volume Family D824D426-8315-405A-A7CD-5B62E549FBAE
        ----------------------------------------------------------
        Encryption Status:       Unlocked
        Encryption Type:         None
        Conversion Status:       NoConversion
        Conversion Direction:    -none-
        Has Encrypted Extents:   No
        Fully Secure:            No
        Passphrase Required:     No
        |
        +-> Logical Volume AC1A071B-63D0-488F-AFFF-D296E446FE6B
            ---------------------------------------------------
            Disk:                  disk2
            Status:                Online
            Size (Total):          914000052224 B (914.0 GB)
            Conversion Progress:   -none-
            Revertible:            No
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS

Assuming you have only one CoreStorage logical volume group named "Macintosh HD," copy (select with the mouse and Cmd-C) the series of numbers and letters right after the words "Logical Volume Group," the top item in the tree (9B4FB14F-DA7D-46EF-BBB9-FD99166C1E2F, in my example).

Now, enter diskutil cs delete <UUID>, pasting (Cmd-V) the number you just copied in place of <UUID>. Some output will indicate that the volume was deleted.

Close the terminal or switch windows to get back to the Mac OS X Utilities window.

Open Disk Utility and click one of the drives printed in red text. You should immediately see a message appear, telling you that an error has occurred with your disk (in my case, it also mentions that the disk will not function as a Fusion Drive in its current state).

Disk Error

Click the fix button.

All the proper partitioning will be done automagically, and your drive will be restored to its former glory. All that's left to do is Restore From Time Machine Backup or Reinstall Mac OS X. The choice is yours.

  • 1
    There are a lot of potential solutions out there for this problem. This one worked for me after all others had failed! – NathanChristie Jun 10 '16 at 2:34
  • does anyone know if this process still works in High Sierra? – dwightk Mar 21 '18 at 15:45
3

I had a similar problem. I created a 30 GB partition and after deleting it there was unused space. I couldn't manually get the original full partition back because of disk errors. So I booted into Recovery (Command + R), repaired the disk with Disk Utility and then the resize to original was no problem. Rebooted and now back to normal. Had no need to reinstall the OS or go into terminal.

2

I know it's a bit late now, but if you can format the blank space as MS-DOS, then Bootcamp Assistant will assume it's a Windows installation, and help you remove it.

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protected by Community Jan 21 '15 at 19:53

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