How to Partition and Resize Mac hard drive on OS X El Capitan
Summary
Disk Utility got a facelift with the launch of OS X El Capitan. But this makeover didn’t go well for a handful of Mac users. Some of them find difficult to perform regular disk management activities on Apple hard disk drives including partitioning the disk, creating, resizing and deleting a partition.
Good News Arriving Soon
Very soon we will need to partition our Mac hard drive in order to make room for macOS Sierra installation which Apple announced this WWDC 2016 in San Francisco.
Tip
But before the time arrives to partition the Mac hard drive for macOS Sierra installation, it is equally necessary to backup the data on Mac startup disk drive to avoid losing any files during the upgrade or installation processes.
OS X El Capitan Partitioning
With the help of screenshots, I will be explaining some basic set of activities that are to be done while partition the OS X El Capitan drive. Alternatively, the same procedure will be explained with the help of a disk manager utility known as Stellar Partition Manager.
Background
I am using an old 40 GB external hard drive to create, resize and delete partition with Disk Utility and Stellar Partition Manager software.
** Resolving Partition Option Greyed Out issue
- Select the external disk from the left side of Disk Utility
- Unfortunately, the Disk Utility partition option is greyed out (see below screenshot)
Solution: Select the ‘Generic USB Disk Media’ and the partition option will become active.
Click the Partition button to start partitioning the external drive
Task 1) To create 3 Partitions of below sizes (using Disk Utility)
- Partition A = 20 GB
- Partition B = ~10 GB
- Partition C = ~10 GB
Step 1) Enter partition name and format i.e. ‘Partition A’ and ‘OS X Extended Journaled’
Step 2) Enter partition size i.e. 20 GB. Press Return and slider will automatically take 20 GB. Else drag the slider to occupy 20 GB of spaces for partition A.
Now select the 19.7 GB of the remaining hard drive spaces and click (+) plus sign. Name the 2 partitions as B and C.
As shown above, the external hard drive is divided into 3 partitions of sizes 20GB, and two almost 10 Gb of partitions. Click Apply to save the changes.
Outcome Looks Good
Task 2) To resize the 3 partitions as below requirement (using Disk Utility)
- Resize ‘Partition A’ to 15 GB
- Resize Partition B to ~12 GB
- Resize ‘Partition C’ to ~13 GB
Now, here the problems arrives
Entered 15 GB for Partition A and pressed Return. The ‘Partition A’ shrinks to 15 GB but created a new partition of 5 Gb, which is unused.
Now as per our second task, we need to create around 12 Gb for Partition B. Let’s see if Disk Utility allows us to do it perfectly.
Unfortunately, neither the mouse slider nor the Size box is accepting the Partition B to expand to ~ 12 Gb in size. The same issue is bothering ‘Partition C’ which is not expanding to ~13 Gb of size either through the partition slider or with the help of the size box.
No Productivity
Since the partitioning as mentioned in Task 2 cannot be done with the help of Disk Utility on OS X El Capitan we will choose to achieve this task with the help of Stellar Partition Manager utility.
Stellar Partition Manager
Task 3) To resize the 3 partitions as below requirement (using Mac disk manager software)
- Resize ‘Partition A’ to 15 GB
- Resize Partition B to ~12 GB
- Resize ‘Partition C’ to ~13 GB
Witness the difference b/w Disk Utility and Stellar Partition Manager
Fortunately, Stellar Partition Manager utility collects all the available free spaces on the Mac hard drive or an external hard drive and uses it efficiently for resizing the Mac partitions.
Now let’s achieve our tasks
** Resize ‘Partition A’ to 15 GB by using the mouse to drag the edge and shrink the partition size from 20 GB to 15 GB
** Time to resize ‘Partition B’ to ~ 12 GB
** Time to resize / expand ‘Partition C’ to claim all available free spaces. In the above screenshot, you can see that Partition C is of size 8.3 Gb and only 1.74 GB of free spaces are available. Hence it will take all the free spaces but this external hard drive is only 40 in size so the final size of the Partition C will be 9.42 GB.
Click the Start button mounted on the top menu bar to apply the changes. Hence, we have achieved the partition-resizing task up to 90% with the help of Stellar Partition Manager utility.
Advice please!! I’m recovering data from an internal mac hd I once had in a damaged Macbook Pro. I only use Windows laptops now and the internal hard drive does not copy the folders over to my WD passport external hard drive. How do I partition the hd so that I can switch the files over for Windows? Is this what is to be done on Bootcamp? Would a typical Mac have this installed or does it need to be installed?
I ask as the options in the above instructions only showed Mac options – nothing particular for Windows.
I was following a guide and got into this problem this is that guy Read More
My brother deleted a partition from external hard drive. Can I recover it using a free Mac data recovery software?
Hi Laura,
Visit free Mac data recovery registration page.
Good Luck.
Thanks,
Hi, I have el capitan and I have 3 partitions but I want to take my third and add it to another partition so that I only have two partitions. Is this possible in disc utility? I accidentally created the third partition because I was trying to make one partition smaller so the other one would increase in size.
Hi Jessica,
Removing a partition from Disk Utility is simple however the available free spaces must get merged into another partition. At times, Disk utility fails to do so. Hence I recommend Stellar Partition Manager application with which you can create a bootable USB. Using boot USB, you can remove the third partition and merge its free spaces to the partition of your choice. Other advantages of the mentioned application are – support for HFS, NTFS, FAT and EXFAT file systems, add, create, delete and hide partitions. Hope this answers your query.
Thanks.
hi there
question i have partition my primary drive to fat format when suddenly the electricity
went down while i am partitioning the drive when i restart my mac the partition that i was making suddenly disappear leaving my 1tb hard drive to half the size of the drive
i was looking for the missing partition but i cannot find it on the disk utility?
can you help me? thanks
Hi harold
Do you have the backup of your hard drive? The partition was lost due to a sudden loss of electricity. You need to format the hard drive and restore your backup. If this doesn’t work then you need to run Stellar Mac Data Recovery to find the recoverable partitions and recover all files from it.
ouch!
thanks for the info maybe need to backup now the files and try to reformat the hard drive
again thanks a lot!
You need to delete your Windows 7 partition without impacting your main Mac partition using the help of Disk Utility. Also remember, that you need to take your backup in case if something goes wrong. Deletion of Windows partition using Disk Utility will result in loss of free spaces. I recommend you use Stellar Partition Manager to perform BootCamp deletion and Mac HD resizing.
Why I need your partition manager tool when Disk Utility can do it for free?
Hi Margaret,
Disk Utility doesn’t merges free spaces available on hard drive to create another partition or help resize already existing partitions. Stellar Partition Manager does that smarty. it collects all free spaces that helps you add new partition as well as resize HFS or NTFS partitions. Hope this answers your query.
Hi, I got a problem as simple as it gets about Mac inbuilt utility, i.e. Disk Utility. Few times ago, I did two partitions of my Mac hard drive, and names them as “Mac HD” with 32500 GB long and another one “Windows 7” with 50353 GB long . Initially, it was planned to install Windows on the 2nd partition, but I didn’t do it, because I have purchased a laptop with Windows 10.
So, Now I want to delete that Widows 7 partition and make my original partition large so that I have just one partition. My main question is, whether enlarging in primary partition would lose in data?
Every time I enlarge my Macintosh HD and click Apply button, it bounces back to its previous size? I have another partition as BootCamp on my Mac hard drive. How can I effectively enlarge the Mac partition with no free spaces wastage?
Hi David,
Stellar Partition Manager is much-advanced disk manager application than Disk Utility and it will surely resolve your partitioning problem. Partition Manager software is available for a free trial.
Regards
My Mac OS hard drive is formatted as Mac OS Extended (Journaled), but it won’t allow me to resize (enlarge) this partition. I haven’t got a ‘drag’ corner. It says something about my startup drive, but, I can’t get the clue about it?
Is this what is causing the problem or something else?
Disk Utility does not let you resize a partition that has a Master Boot Record (MBR). You can see at the bottom of the window in the information if that is the case for your partition. These type of partition are the ones that are used mainly for booting a Mac system.
I am still running OS X Yosemite and had older OS X Mavericks installed on another partition. Due to some glitches on mavericks I restored it using Recovery HD but later formatted it. However, to my surprise I see that no (-) sign is available to delete the Mavericks partition. I really want to remove it combine the Yosemite into a single hard drive. How is it possible to do?
Hi Capitan,
Stellar Partition Manager creates a bootable USB that allows resize, deleting and formatting Mac partitions including boot volume. With this bootable USB you can resize the partition to take available free spaces. Hope this helps.
I want to create 2 partitions on my 128 GB SSD but Disk Utility Partition is greyed out. I tried switching the root and child drive but the Partition option is still greyed out. I looked for the solution but I came to know that I need to format the hard drive in order to make the Partition button active. I don’t have another disk to backup the SSD nor my Mac HD have enough space. How can I partition the SSD without formatting?
Hi Rodalph,
Stellar Partition Manager utility can help you create / resize SSD partitions as per your desired size. You need to register the utility in order to access all its features. Your SSD is a startup disk hence the software will first create a bootable USB which will provide you with facility to perform all partition management activities. This utility does have an upper hand over the Disk Utility.