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Sunday, September 19, 2010

Grow HFS+ partition on Mac OS X without Disk Utility

I have Boot Camp set up, and I had shrunk my main Macintosh HD partition to make room for an Ubuntu partition. Turns out I didn't really want it as much as I thought I did, so I used a GPartEd live CD to remove the partition. However, it wouldn't let me grow it back. Turns out GPartEd can't do that. I called AppleCare to ask what I should do, and I was actually on the telephone for a little over an hour. They told me to use Disk Utility to grow the partition. I tried, however, and it gave me the error message "Partition Failed with the error: Filesystem resize support required, such as HFS+ with Journaling enabled." They tried to help, but they weren't able to solve the problem. I came across this forum post, however, and it mentioned the diskutil command, more specifically the resizeVolume subcommand. I tried this, and it worked! Here's what to do if you ever have the same problem:
  1. Open Disk Utility.
  2. Select the volume you want to grow, and click Info in the toolbar.
  3. Note the Disk Identifier (from here on referred to as ????), and optionally quit Disk Utility.
  4. Open the Terminal.
  5. Type the following command: diskutil resizeVolume /dev/???? limits
  6. Note the Maximum Size (not the part in parentheses.)
  7. Type the following command: sudo diskutil resizeVolume /dev/???? [maximum size]
  8. Enter your password if prompted.
In Step 7, do include the GB after the size, but don't put the space in between.

Here's a screen transcript of what I did in the Terminal in case it helps (highlighted lines represent what I typed):


Pol said...

GREAT TIP! I had pretty much assumed that this was an impossible feat by now - after so much searching I only could find that you couldn't do this from inside the OS, and that Gparted can't grow HFS+ anyways. This was way easier than that anyways. Thanks a bunch.

Anonymous said...

Beautiful! Funny how this works where the GUI version of Disk Utility doesn't. You are my newest net hero.

Anonymous said...

Life saver thank you got me out of a jam at work. I agree you are my newest net hero

DdStclaire said...

Worked like a charm, awesome! You saved me SOOO much work! I'd hug you if I could. Thank you! Thank you! Thank you!

jbob said...

Lifesaver!! Thank you so mucking fuch! I had installed ubuntu and refti and was totally lost due to the 'partition failed with error file system resize support required' message, this totally saved me. Was starting to despair. Thanks so much.

MCAndre said...

My partitions were having the same issues. I tried gParted, couldn't grow the HFS+ partition. I ended up deleting all partitions and using an old Mac install DVD's Disk Utility to create a new HFS+ partition for the whole disk, as I plan to sell the Mac anyway.

You could try using hdiutil, good luck.

Anonymous said...

I tried your trick, encountered an error message:

Error obtaining resizing information (is this a Mac OS 9 compatible "wrapped" HFS volume?)

It has something to do with GUID vs MBR? Still needs a solution...

dotnetCarpenter said...

You get Error obtaining resizing information (is this a Mac OS 9 compatible "wrapped" HFS volume?) if your are using MBR as partition map scheme. Unfortunately diskutil does not work with MBR and GParted can not grow an HFS+ partition...

Andreita c said...

it works great thanks so much for sharing!!!

WarpinWolf said...

Wow - after numerous attempts - it works. I did use VirtualBoxManage to increase VDI size from 20GB to 30GB. Although the "limits" did only show 20.6 GB I simply did increase it by 30GB - et voila!


Unknown said...

Just to support the Maestro's work.
Sometimes you might get an error saying Volume not supporting resizing.
In this case, instead use mergePartitions.
For more info on how to use mergePartitions, type 'diskutil mergePartions' in your terminal, then press enter on you keyboard and your Mac will tell you how to use it.
Very useful trick.