Resizing your OSX HFS+ Partition (for free)

OSX is running superbly. But its nice to dual boot isnt 😉 Here’s how to resize your MAC OSX HFS+ partition in order to install another OS of your choice:

1. Disable journaling on your drive:

i. Rename your HD, this will make the command easier. Click on the Hard Drive icon on the desktop, press enter and type something simple. I chose ‘hd’.
ii. Open up a terminal and type:

sudo diskutil enableJournal hd
sudo diskutil disableJournal hd

(verify that it says Journaling has been disabled)

2. Now you can reboot your you mac with you chosen install disk/device of choice.

** Remember to press ‘c’ on bootup if you are booting from the cdrom/dvd drive.

3. Start an install of your chosen OS as normal, until it comes to the partitioning section:

i. Choose ‘Go Back’ and open up a terminal and type:


Press ‘p’ to show the current partition layout and pay particular notice to the start number.

Now we resize the current HFS partition with the following command:

resize 3 135MB 20GB

This resized my 40GB HFS partition (3) to 20GB leaving 20GB free space for installing the new OS.

You can press ‘p’ to confirm the resize.

Now you can press ‘q’ to quit and type exit to return to the installer of your choice.

I simply then installed DebianPPC using the available free space. It works a treat!

About Louis

Louis is a Developer and all round geek from the UK with a keen interest in web technologies and mobile applications. When not playing with code, he is probably rebuilding a Linux server or watching a Netflix marathon!
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