So, I have a Mac Mini with a 160GB drive (it's an old model but it's only for testing). It had 4 versions of OSX on it but one needed more space so I removed the oldest version (Lion) and want to keep it to "latest", "latest-1" and "latest-2".

I've got to the situation where I now have the 3 OSes I need and I've managed to resize the partition for the one which was full so it now runs. But I'm left with a load of free space that I'd like to split between the others so that they don't fill up either.

Disk Utility screenshot

Hopefully it's clear in the screenshot, but when I want to do this resizing, I have this situation where I can only select that single "partition" and I can't resize it. I can resize the Mavericks partition itself OK, but because that grey section can't be resized, I can't move it or resize the Yosemite/Mountain Lion partitions

mac-mini:~ user$ diskutil list
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *160.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Yosemite                42.8 GB    disk0s2
   3:                  Apple_HFS Mavericks               50.9 GB    disk0s3
   4:                 Apple_Boot Recovery HD             650.0 MB   disk0s4
   5:                  Apple_HFS Mountain Lion           37.7 GB    disk0s5
   6:                 Apple_Boot Recovery HD             650.0 MB   disk0s6

diskutil from the command line doesn't show a block of free space, but I can see it in the GUI Disk Utility, I just can't do anything to resize that grey area to match the size of Mavericks, which I think I need to do in order to change the "split" between the partitions and add more space to Yosemite/Mountain Lion.

Any other tools I can try apart from Disk Utility, preferably freeware or time limited trials since I'm only going to need to do this once?

  • The safest + quickest way is through the GUI. If using GUI, u need to boot into a given partition to resize it.The reason you’re able to resize Yosemite is bc it’s your boot volume. You can’t resize the other partitions through the GUI because you they aren’t. So - boot into the Mavericks partition (hold down OPTION at the chime) > select the Mavericks volume (not it’s recovery volume). Once booted and logged into your admin account on Mavericks, open Disk Utility. Attempt to resize the Mavericks partition to fill the grey void. This should work. If it doesn’t, it’s still the first step.
    – njboot
    Feb 10, 2015 at 9:13
  • I don't want to fill the void with Mavericks, that's the problem. Mavericks is now 50GB which is big enough, I want to expand Yosemite and Mountain Lion to also be 50GB, using the space contained within that grey void which I can't resize. edit - also, I did try from within Mavericks and that wouldn't let me resize the void either, hence booting to Yosemite to see if I could resize it when not in use, but that didn't work either so the screenshot was taken from within Yosemite.
    – gac
    Feb 10, 2015 at 9:29
  • Short answer is No, looks like the Yosemite partition is full unlike the Mavericks partition.
    – Maximus
    Feb 10, 2015 at 9:42
  • Nope, none of them are full right now, but the Yosemite and Mountain Lion partitions are now smaller than Mavericks so I'd like to use that large void of free space to increase them to match. Just doesn't seem to be possible with Disk Utility which is hugely frustrating.
    – gac
    Feb 10, 2015 at 9:48
  • @gac AFAIK without third-party tools you can't move start blocks of Mac partitions to a lower address (e.g. if the ML partition starts at block 1000 and ends at block 1249 [size=250] you can't change the start block to 900 to increase the size to 350. Additionally you have 2nd recovery HD. So please add the output of gpt -r -vvv show /dev/disk0 entered in Terminal.app to your question.
    – klanomath
    Feb 10, 2015 at 11:32

1 Answer 1


I recommend downloading a copy of GParted from here: http://gparted.org/download.php

Then either:

  • Burn that iso file to a CD and then boot from the CD.
  • Or, create a new partition on your disk, use Disk Utility to Restore from the iso file to the new partition, set that partition as the startup disk, and finally boot into GParted.

GParted is the king of partitioning tools.

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