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Tom Nelson

How to Resize a Disk Partition Without Losing Data

By February 8, 2011

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I get some interesting questions sent my way, and this weekend was no exception. A long-time About: Macs reader wondered if it's possible to resize a disk partition on his Mac without losing any data.

How to Resize a Disk Partition Without Losing Data

Seems he needs more room for his ever-growing library of images. He originally split a disk into multiple partitions, but as his collection of pictures grows, the image library partition is fast running out of room. Luckily, he has another partition on the disk that isn't really being used, and he's willing to give up that partition, or at least steal some room from it.

I sent him off to peruse the Disk Utility - Add, Delete, and Resize Existing Volumes With Disk Utility article, which contains step-by-step instructions for resizing a disk partition.

There are a few restrictions for resizing a disk partition, and it's a good idea to know what these restrictions are when you first plan to partition a hard drive. If you know the restrictions in advance, you can probably get away with resizing a hard drive partition later, if the need arises.

March 19, 2013 at 1:37 pm
(1) M says:


I tried the Disk Utilities method as described in the article, but it says “You can’t resize tehe partitions on this disk because it uses the Master Boot Record partition scheme. This partition can’t be modifed.”

Any insight? It’s a Lacie disk, split between one partition for Mac and another (in “MS-DOS (FAT)” FORMAT) for WinDoze.


March 19, 2013 at 3:09 pm
(2) Casey says:

The problem is the mix of Apple’s HFS+ and MS-DOS formats on the drive. Apple’s disk utilities ability to resize a partition is limited to HFS+ formatted drives.

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