Apple's built-in disk management utility for the mac. Erases, formats, and restores volumes and drives.

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Disk structure error reported in Onyx but not fixable via the Disk Utility in Recovery Mode

On Yosemite 10.10 Onyx returns the following error: Error: -69845: File system verify or repair failed Underlying error: 8: POSIX reports: Exec format error The disk needs to be repaired. I ...
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53 views

Cannot delete Free Space on iMac 5K after I deleted Boot Camp partition with Disk Utility

I had Windows 10 installed via Boot Camp, and everything was running smoothly, except I did not think ahead when I had made the partition initially. So as I was using Windows more, I eventually ran ...
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1answer
145 views

Fusion Drive with missing partition

Initially my Fusion drive (1TB data disk + 240 GB SSD) consisted of a single partition where it was installed El Capitan, then I split the fusion drive into two partitions, the second partition I ...
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45 views

Install rEFInd on separate partition (Errors)

I am trying to install rEFInd a separate partition but have run into an error. I'm doing this because I want to install Ubuntu on my other partition (separate from my Mac and and rEFInd partition). ...
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12 views

Recovering a partition on a flash disk

The other day my 128gb flash stick refused to be recognised when I plugged it in, giving me a 'failed to initialize' error with options to format it or eject. This was particularly frustrating because ...
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0answers
21 views

How to add addional HFS+ partitions after installing Windows with Bootcamp

The goal is to create a few extra HFS+ partitions after running the Bootcamp utility while not breaking Bootcamp's boot-ability. I am Running OS X El Capitain, and I only have a single disk drive to ...
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2answers
195 views

Boot from USB in macbook pro mid 2012

I have removed everything from my macbook pro. Now, how can choose USB as a startup disk? I tried using option "SHIFT" keys also cmd+R. Nothing is working. How can I solve it? I am using Mid 2012 ...
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1answer
484 views

Cannot install OS X in recovery mode

I want to reset my iMac (late 2014, 1 TB Fusion Drive) to factory settings. As I want to set it back to Yosemite, I am using Internet Recovery (Command-Option-R) as I have installed El Capitan in the ...
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3answers
991 views

Unable to shrink a partition in osx 10.10

Hi, I installed windows using bootcamp, but i made the mistake to make the bootcamp only 20gb, so i want to expand it. I found a way to do so, but firstly i need to shrink my other partition - ...
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49 views

External disc partitioning gone wrong

I would appreciate any help as this situation is beyond my skills. I was trying to follow an internet instruction for putting an OS X Installation on my WD external drive using my MacBook, to ...
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1answer
69 views

USB drive appearing as two different devices

I just plugged an empty flash drive into my computer, and it thinks there are two drives - the flash drive I expected, and a small CD-ROM drive. Here is the relevant section of output from running ...
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1answer
174 views

Ubuntu Disk isn't showing up at Boot

I recently installed ubuntu on a flash drive, following all of the instructions on the ubuntu website. When I started up my mac, it didn't appear in the boot menu. Has this happened to anyone else ...
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25 views

Restore RAID Mirror?

I had a 3TB mirror using Apple software RAID on Mavericks—the two disks are in a USB3 JBOD and the USB3 card in my Mac Pro only works with Mavericks or older. Last night I demoted one of the disks so ...
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90 views

What are the advantages or disadvantages to Logical Volume Groups vs traditional partitions

I recently installed a new 3TB hard drive on a Mac Pro (3,1) running yosemite. With other hard disks, I had previously installed the hard disk and then erased in disk utility getting the traditional ...
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2answers
89 views

Disk Utility stuck at exit code 0 during partition restore (in Recovery Mode)

I have an iMac running OS X El Capitan. I tried to use the disk utility in normal boot to restore two partitions into one but it would exit with an error (exit code 8) and delete the second ...
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0answers
72 views

How to create (the missing) El Captain recovery partition? [duplicate]

I upgraded from Snow Leopard to El Captain. Before upgrade I had a bootcamp partition, and a third FAT32 partition. this caused some complications in the upgrade process and I had to delete the El ...
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48 views

Scripting a Partition Scheme for CoreStorage - Mac

I've read a lot of information about the CoreStorage/Fusion Drive setup. In our environment, we work on a multitude of configurations of Macs, many with multiple operating systems on them. As such, ...
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1answer
125 views

Help partitioning “free space” with utility disk

I've been trying to partition my harddrive to have ~50 gb of unallocated space (right now there's one partition with the operating system on it, so I would like to have that plus the free space). This ...
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1answer
61 views

How to resize the main volume to its original or full size?

I followed the instructions mentioned in one of the threads on this community to expand the Macintosh HD volume to its full volume. I rebooted with cmdR to Recovery Mode, opened Terminal, entered ...
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2answers
2k views

Apple Hardware Disk Utility Unallocated Space on my Hard Drive

While trying to get Boot Camp set up on my MacBook Pro 15 inch Retina 2015 it asked me to partition my hard drive. Doing so I partitioned my 1 TB hard drive so that it dedicated 750 gb to mac and 250 ...
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1answer
44 views

Is there an easy way to install Linux similar to Boot Camp?

I've so far been using Disk Utility to partition my Mac's drive and install Linux, but is there an easier way to do it, using something similar to Boot Camp, or a third-party software application that ...
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1answer
72 views

Startup Disk Full: Core File

The storage on my start up disk is being consumed by some kind of core files labeled as cores:1234 (numerical digits change). I downloaded OmniSweeper, which helped me locate these files and aware ...
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1answer
1k views

Bootcamp Failing with Error: “The startup disk cannot be partitioned or restored to a single partition.”

I have a 21.5" Mid-2010 iMac i3 in which I am trying to install Windows 8 on. When I went into bootcamp, I received the ever so common error of: When I went to the newly designed disk utility, it ...
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41 views

Merge all partitions back to single volume

I was trying to install windows 10 on my Retina Mid 2015 MBP using bootcamp, and ran into a few problems during the installation. Without going into too much of detail, this is what i have right now, ...
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0answers
17 views

How to fix this hard disk on a virtual machine?

I have been using OSX on a virtual machine for some time, for developing purposes. From today, I'm starting to have hard disk issues. The Disk Utility Tool says that the hard disk has 107.37 GB, but I ...
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12 views

Schedule regular filesystem verification

I recently had a baffling several days troubleshooting some odd network problems, which was eventually narrowed down to my MacBook's Wifi adapter and then finally fixed by performing a disk repair to ...
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0answers
207 views

SD Card mounted but not accessible in Finder (OS 10.10.5)

On an early 2015 MacBook Air running 10.10.5, Finder will not show SD cards, despite the disk showing up in Disk Utility. In Finder preferences, I have set external disks to be shown on the Desktop ...
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13 views

can I recover merged HFS+ partition with TestDisk

I have merged three HFS+ partitions into one using diskutil. The partition in the middle has some very important files. Using Stellar Phoenix Recovery's recover lost partitions option, I could see ...
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1answer
49 views

USB Hard Drive HFS+ Encrypted Partition Formatted / Recovery

I have a WD 1TB USB External Hard Drive that was accidentally formatted. I had formatted the disk and started writing an ISO to the disk (less than 5 seconds), when I realized it was to the wrong one. ...
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192 views

After installation of El Capitan, Bootcamp: “A disk read error occured”

Prior to installing El Capitan, my Windows 8.1 installation was running fine and dandy. Now when attempting to load into Windows via rEFIt, I am faced with A disk read error occured. Press ...
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1answer
425 views

How to make Macintosh HD size the same as SSD

So today, I tried dual-booting my late 2013 rMBP on El Capitan with Windows 10. I got to the step within Bootcamp where it was partitioning my SSD, and I went ahead and played a game of Super Smash. ...
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23 views

Are slow format speeds indicative of more severe hard drive problems?

I have an mid-2011 iMac, that has 4GB of RAM and a 500GB HDD (not SSD). Over the past few months I have experienced: Fairly frequent beach balls/general system slowdowns A worrying number of errors ...
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21 views

Can't find storage after fixing EFI system partition error

I followed How to fix the error: "This disk doesn’t contain an EFI system partition"? In the final step sudo dd if=/dev/disk1s1 of=/dev/disk0s1 I cloned an existing ESP from an internal ...
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63 views

Disk utility reports wrong partition size

I am running El Capitan and recently deleted a bootcamp partition. However, I have noticed that Disk Utility is giving me erroneous values when it comes to partition size. When I click on the HDD, it ...
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3answers
2k views

How can I resize a partition on OSX 10.10.5

I have a Mac with OS X 10.10.5 on a HD which had 4 partitions. Using Disk Utility I deleted one of the 4, intending to slightly grow the 3rd (containing the OS), leaving space for a new partition to ...
2
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1answer
676 views

Creating a partition in unallocated space

I left some unallocated space on my external HD (around 200 GB) and now I would like to create a partition on it using gpt in terminal since the Disk Utility tool on El Capitan is not even showing the ...
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0answers
189 views

Fixing damaged hard drive after OSX update

I recently tried updating my Macbook Pro Retina to OSX El Capitan, however believing this to be a simple routine update, I did not backup my computer. Of course, the update was unsuccessful, somehow ...
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1answer
53 views

Stuck on 'Preparing to partition disk'

When I add a new partition it gets stuck on 'Preparing to partition disk'. The new partition is in some empty space in the middle of the disk. As a result of the partition not being there, Windows ...
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1answer
895 views

Accidently deleted some small sized partitions when installing WIndows(Bootcamp). OSX Partition wont boot

I tried to install Windows 8 into my Mac via Bootcamp. I booted into the Windows 8 Installer and had issues formatting the drive that I partitioned for the OS. Like an idiot, I deleted all of the ...
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0answers
63 views

Can't format new SSHD?

I just got a new SSHD, but when I tried to put it in my early 2011 13" MBP and format it from a bootable drive, Disk Utility kept giving me the error message: could not mount disk0s2 with name (null) ...
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0answers
233 views

Missing SSD space on MBPr 13, El Capitan

I have the following problem: I had two partitions, one was ~190 GB, and another ~60GB. Then I wanted to delete the second partition and resize the first one. The deletion went well (I suppose), but I ...
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2answers
1k views

Disk utility, shrink 1 partition, expand the other

I have two partitions on my external HDD, I shrinked 1 partition (Macintosh Lion) in order to expand the other (Macintosh HD), but I can't drag the lower right corner to expand of the 'Macintosh HD' ...
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1answer
501 views

I removed Boot Camp the hard way, but then I got a Windows error anyway. Should I be concerned?

The short version: I was running Boot Camp on my Retina MacBook Pro, but I decided just recently to ditch it because I never use it and I'd like to reclaim the space. The official method of removing ...
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0answers
118 views

Recovery mode Disk Utility can't see new internal hard drive

Lots of similar questions, but no one seems to be having the exact problem I am. Hard drive on my mid-2012 MBP (Mavericks now, but originally Lion) died; I do have backups (including a clone of the ...
2
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1answer
204 views

Deleted Macintosh HD. Need to create a new partition/ partition table

I was trying to install El Capitan. I went to erase Macintosh HD in recovery> disk utility as I wanted to do a clean install. It then deleted the Macintosh partition then gave me an error code saying ...
0
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1answer
222 views

How do I resize an ex-CoreStorage volume?

I've got a Macbook Pro Retina (with the PCIe drive ‘blade’, instead of a traditional 2.5" laptop drive). I've recently upgraded the internal drive from 500GB to 1TB, and dd'd the old drive over the ...
8
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3answers
42k views

Can't create partition on free space with Disk Utility [duplicate]

I have created new partition by selecting free space option and now I can't merge it or recreate it. I have tried to use iPartition to create a new partition on free space but it said I have no ...
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130 views

how to resolve disk partition issue in OSX 10.10.5?

Using Boot camp assistant I have created a partition and installed Windows 7 OS to work on both Mac as well as windows (Dual boot). But later on deleted the windows OS partition(Could not remember how ...
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0answers
48 views

How do merge the free space to my Macintosh HD partition?

I have approx. 370 GB of free space from which I want to merge 200 GB to my Macintosh HD disk. Can anyone please help me on this? I am not even getting the resize option there. System version: ...
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2answers
362 views

How to Erase External USB Drive Which Won't Mount & Isn't Recognized

Before starting, let me mention that I have ALREADY read the following thread in its entirety, and it did not help my situation: https://discussions.apple.com/thread/4832305?start=0&tstart=0 I ...