I have a Boot Camp partition on my MBP. When initially setting up the Boot Camp installation I set this partition to be quite large but now I wish to utilise more of that space in the Macintosh HD volume.

I've booted into Windows and used Disk Management to shrink that volume, so there's now just over 200GB of unallocated space on the drive.

I now wish to 'incorporate' this unallocated space into the Macintosh HD volume, but Disk Utility (the GUI version) doesn't allow it.

I've also tried

Terminal > diskutil resizeVolume disk0s2 0

I used 0 because diskutil tells me "A size of zero will cause a grow fit-to-fill." However, this command responds with "Volume format does not support resizing" and while that response might be very clear to someone else, I'm not sure what it's telling me. Is it because the unallocated space was previously formatted as NTFS?

Am I doing this the wrong way? Do I just need to tweak my Terminal command? What is the correct way to extend my current Macintosh HD volume into that unallocated space?

  • read this question to see what additional information may be required before anyone can suggest a possible fix - apple.stackexchange.com/questions/153523/… & look at the answer to see how much fun it might be ;)
    – Tetsujin
    Dec 13, 2015 at 13:10
  • Jeez, I'm not willing to use a partially-destructive or a totally-destructive method. Do I really have no other options to extend my volume?
    – awj
    Dec 13, 2015 at 13:19
  • 1
    No. The 'official' way to to it is to uninstall Boot Camp, which will reclaim the entire volume, then reinstall at a new size. I'm actually surprised you managed to resize the volume from within Windows without it breaking the entire drive. That's a big no-no.
    – Tetsujin
    Dec 13, 2015 at 13:29
  • Without the additional information requested all I can suggest is I'd backup the Boot Camp Partition with Winclone, remove the existing Boot Camp Partition with Boot Camp Assistant, create a new smaller right sized partition with Boot Camp Assistant and then restore Windows from the Winclone Image. Dec 13, 2015 at 13:35
  • I ended up using BCA to remove the Windows installation, then reinstalling with the desired partition sizes. Not the best way, and it certainly wasn't fun, but I couldn't see that there was any proper and safe way to achieve this.
    – awj
    Dec 13, 2015 at 19:17

1 Answer 1


Change partition size only with Bootcamp Assistant.

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