I have deleted the primary partition from my computer, and installed Mac OS Lion on a second. Now I want to enlarge the "Lion" partition, to make it fill the whole drive. I've been struggling to figure out how, can anyone help?

This is how the partition looks:

<free space>  (351 gb)   (not formatted)
<lion>        (147 gb)

3 Answers 3


Lion's Disk Utility can resize partitions, but only by adjusting the "end" of the partition, not the "beginning". You can do what you need using Disk Utility, but it would be a multi-step process:

  1. Create a new partition in the 351GB of free space at the head of your drive.
  2. Use Disk Utility to do a "restore" from the existing partition to the new partition.
  3. Reboot from the new partition and make sure it works and has all your files.
  4. Now delete your old 147GB partition, and stretch the end of your 351GB partition to fill that space.

Another application to do that is iPartition. It's in the same price range as Drive Genius. I've been using if for a few years now and never had any problems with it.

As lupincho wrote create a backup before you preform any operations on partitions.


Drive Genius presumably is able to resize partitions, but is somehow pricy. I haven't used it, and as with all such pieces of software -- make sure that you have backed up all you data before utilizing it.

This said, if you have an extra external drive you could backup the second partition to an image or partition on the external drive using SuperDuper! or Carbon Copy Cloner; then repartition the original drive and restore the system from the image that you've created at the first step. If you have Time Machine backup, you could use that to restore, although I think it is slower.

Again -- whatever you do, make sure that you have a backup of all data.

  • Thank you for the quick answer. If I use Carbon Copy, am I able to backup the entire drive.. and not install a new mac os x again ? - Can I restore the drive from disk utility in "restore mode" (cmd + r at startup) ?
    – jakobk
    Commented Apr 8, 2012 at 19:41
  • Yes that's the point of cloning a partition. See: help.bombich.com/kb/usage-scenarios/…. What you need to do is to clone the system partition to an external disk or partition, making it bootable (everything that was on the external disk or partition would be lost). After that boot from the external disk. Once the OS is running, you could repartition the internal disk with Disk Utility. Then you could clone the bootable external disk (partition) back to the only internal partition. You don't need to use restore mode.
    – lupincho
    Commented Apr 8, 2012 at 19:51
  • Note that the Trash and some system temp files would be lost when cloning: help.bombich.com/kb/explore/…
    – lupincho
    Commented Apr 8, 2012 at 19:55

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