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

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Disk Utility Error Message - Missing EFI + MediaKit

Previously setup was with 2 partitions, one for normal use while the other had the Lion Install ESD on it, used when I installed some time ago. The other day my machine suddenly shutdown and when I ...
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1answer
563 views

Time Machine Drive Failure

So, I started up my computer a couple days ago, and OS X reported that my Time Machine Drive had some damage and that I could view files, but not copy anything to the drive. After verifying with disk ...
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Recurring “error code -50/invalid argument” resolved by reboot, better solution sought

I'm using an old iBook G4 (PowerPC) running Tiger to serve iTunes to the house. For the past week or so, the mac boots fine, and then sometime during the day starts generating An unexpected error ...
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1answer
1k views

Why is my boot partition listed as Unmounted in Disk Utility?

I recently experienced a kernel panic ("your mac must restart...") due to an issue with Macfusion, so after the reboot I loaded Disk Utility in an attempt to verify the disk in case something was left ...
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1answer
4k views

Do persistently incorrect disk permissions indicate a disk should be replaced?

Something is wrong with my Mac, as indicated (and still unresolved) in the question: What is the Sixth Step of MacBook Repair? One possibility is that the main disk is faulty. Disk Utility reports ...
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9answers
16k views

Macbook HD “Other” all the Sudden Almost Full

As you can see in the below image, my HD "Other" category is almost full. A couple of days ago, I randomly kept getting a popup saying that my disk was almost full. Then I went in and noticed the ...
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2answers
3k views

How can I mount an encrypted disk from the command line?

When I type diskutil mount disk3 in the terminal, it says Volume(s) mounted successfully. However, the disk is not mounted and I can confirm this by opening the GUI of Disk Utility.app and also the ...
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1answer
337 views

I know how to repair disk permissions. But… Who broke them?

One of the common Mac troubleshooting steps everyone always seems encouraged to try first is to "repair disk permissions" in Disk Utility. This process usually finds random odd problems, fixes them, ...
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3answers
3k views

How do I merge System partition with another HFS+ partition without data loss?

My hard drive is split in three visible partitions: System, Data and Backup. I'd like to merge System (OS X Lion) and Data into one partition without data loss. Disk Utility won't let me resize the ...
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4answers
11k views

SD card is read-only, all Disk Utility options grayed out

I'm using Lion (10.7.3) on a mid-2010 MacBook Pro. I just got a 32GB SD card and formatted it with my camera. I'd like to transfer some files onto it from my computer, but the card seems to be ...
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2answers
666 views

Move complete Lion installation to another physical drive

is there a way to completely move my OSX Lion to my new SSD without reinstalling? I came from Windows and Linux to OSX and i thought maybe it is possible to simply change the bootloader config after ...
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1answer
1k views

What is the blue section of a partition in Disk Utility?

What is the blue section at the top of this image (above Macintosh hard drive partition)? Is it another partition, it only seems to exist on this partition when I create a new one. Where do I find the ...
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2k views

Why can't I write to the last block of my SDXC card on my MBP?

I have a 64GB SanDisk SDXC memory card which I would like to use with my MacBook Pro and its SD card slot. However, I am having some trouble formatting/partitioning my SD card and I can't figure out ...
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2answers
30k views

Cannot Unmount Mac OS X Base System Disk

My Mac running Lion was being slow, so I was decided to reinstall OS X. I don't have any Time Machine backups. Everything went file, but in the middle of the installation, it got stuck, and later the ...
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7answers
7k views

Partitioning secondary internal hard drive failure

Looks like my 2nd HDD became a brick. I tried to partition it via Disk Utilities/booted from recovery partition/diskutil to no luck! I got vague/strange errors such as: unable to unmount, or: ...
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4answers
6k views

How do I repair permissions of a specific directory?

I want to repair permissions of a user defined directory along with it's subdirectories. How can I do this? So far, I've looked for options in finder and tried to drag the folder into Disk Utility. ...
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2answers
2k views

Unable to create a partition to install Mac OS X

When I try to install Mac OS X there is no partition for me to choose. I tried to create a partition and got the error, "Partition failed with the error: Couldn't unmount disc." Anyone have a clue? ...
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1answer
383 views

Recover files from one volume to another on the same Drobo?

One evening we had a momentary power outage, causing sudden shutdown for my Mac mini and the attached Drobo (4 bay). When the system came back up, only one of the two volumes mounted on the desktop. ...
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1answer
787 views

invalid ISO file created by disk util?

In order to install Windows XP on Virtual Box at my new MacBook Air, I need to create an ISO file of my WinXP install CD. My Laptop (MacBook Pro / Lion) comes with the Mac Disk Util and that app can ...
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1answer
236 views

How do I format a (non-formatted) drive when the menu options in the Disk Utility are greyed out?

So I tried installing Lion on an old (white) Macbook, but first I wiped by my drive clean. Just to find out that I only had 1GB memory and Lion requires 2GB. Now the drive is clean, with no ...
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1answer
529 views

OSX Lion Disk Mounter

I seem to have broken something in my OSX Lion install. Whenever I insert a SD/CD-ROM into the machine I have to go into Disk Util to manually mount it. This happens quite a lot and is getting on my ...
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3answers
2k views

Secure erase drive in Single User Mode

My 2007 Macbook Pro has suffered from a failure of its GPU and will now only boot in Single User mode. I want to sell it on eBay for spares, but obviously I don't want a hard drive with live data ...
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2answers
6k views

How can I partition my Macbook Pro's hard disk?

I'm about to install Linux on my new Macbook Pro. In order to do this, I need to resize my Mac OSX partition to allow some free space for Linux. I've booted into the Recovery HD and started "Disk ...
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2answers
1k views

How can I repair a hard drive that Disk Utility and Disk Warrior can't fix?

I have a Mac Pro running Mac OS X Lion, and one of my hard drives has acted weird since attempting to repair permissions. I used Disk Warrior, but it says the HD can't be rebuilt. When I try to format ...
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149 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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1answer
638 views

What do Verify Disk and Repair Disk actually do in Disk Utility?

I've recently been suspecting problems with my hard disk and saw another answer here on AskDifferent recommending Drive Genius or Disk Warrior. I thought I'd start thought by using the built in Disk ...
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1answer
1k views

External HD Shows up in Disk Utility, but I can't access it

I have an External 1TB hard drive that has been corrupted, it was so corrupt that I had to abandon the files on it. So now I'm simply trying to erase it so I can begin using it again. But here's the ...
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1answer
4k views

Disk Utility says: “Error: This disk doesn't contain an EFI system partition.”

After a clean install of Lion, followed by partitioning which again was followed by a installation of Ubuntu, I noticed some error messages of Disk Utitity. When verifying the volume I get told that ...
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1answer
827 views

Solving a problem on a MacBook Pro 5,1 with an OCZ Agility 3 SSD

I installed Mac OS X lion on an SSD (through USB) after checking the firmware was the latest version (2.15). When I transferred the SSD into the MacBook Pro (like i usually do after an install) but it ...
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3answers
2k views

Disk utility can't add partitions

I have two partitions - one with Mac OS, and another with Windows 7 (created by Bootcamp). Now, I want to create two more partitions for Linux - LINUX and LINUXSWAP. I open Disk Utility and specify ...
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3answers
46k views

How to resolve error: “Couldn't modify partition map because file system verification failed”?

I upgraded to Lion and decided I no longer want 100 GB of my drive devoted to Boot Camp, I never boot into Windows, I just use it as a VM anyways. So I deleted the boot camp partition using disk ...
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1answer
300 views

On the Mac, what if Disk Utility is used to mirror two hard drives, one is 1.5TB, and the other is 2TB?

If I happen to have two external hard drives, one 1.5TB and then other 2TB, and use Disk Utility to mirror the two drives, will there be any problem? Can it be mirroring just for the 1.5TB portion, ...
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2answers
3k views

How can I reformat my hard-drive?

I am in Disk Utility under the Erase Tab. The Format section is grayed out even though I have my main disk selected. The only buttons active are Erase Free Space, but I want to reformat the entire ...
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1answer
533 views

How do I move Mac and Windows partitions to single Hard Drive?

I have this scenario: 600 GB Hard Drive, using Master Boot Record 300 GB Windows 7 x64 Parition, NTFS 300 GB free Space 1 TB Hard Drive, Guid Parition Table 730 GB Data Partition, exFat Two More ...
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2answers
258 views

Checking number of reallocated sectors of HDD through Disk Utility, Mac OS X

My MacBook was purchased in 2008. Yesterday I checked the number of reallocated sectors of the hard drive using Disk Utility. It showed there were no reallocated sectors. That seems strange since I ...
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2answers
2k views

Disk utility in command line

I'm looking for the CLI equivalent of "Check disk" and "repair disk" in Disk Utility. I think fsck is involved but I don't know with which options, and if it's the only program run.
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3answers
9k views

Deleting a partition in Disk Utility fails. (Error: -69879)

This is the output in Disk Utility: Disk Utility cannot modify this disk because it contains CoreStorage physical volumes. Use command line distil instead. The selected partition won't be ...
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2answers
6k views

Changing a Volume's “Device / Media Name”

I know a Mac volume can be renamed... obviously. But if you look at the output of diskutil you will see that a volume also has a "device name" that corresponds to the name it was given when it was ...
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1answer
3k views

Why won't disk utility let me remove a partition from my external hard drive?

I have an external 1.5 TB hard drive split evenly with a partition for backup and a partition that was used for Time Machine on my previous computer (OS X Lion). Now I'm using this hard drive with a ...
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2answers
440 views

Repartitioning after Bootcamp problems

When I first got my MacBook Pro, I installed Windows 7 via Boot Camp. A couple months later I wanted to install Ubuntu and have a triple boot. I followed this tutorial: triple-boot After I finished ...
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2answers
1k views

Is it safe to enable the hidden disk image formats and debug menu in Disk Utility, and what are its purposes?

I'm primarily interested to know whether installation of Lion included the Recovery System. I understand you can enable extra formats and debugging in Disk Utility, using the following commands: ...
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4answers
8k views

Unable to increase Macintosh HD partition size with data in a subsequent partition

I can't make my main Macintosh HD partition bigger. It's limited by the FAT partition in the middle, which seems to be frozen, I can't move it down to make space for my main partition. To get some ...
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1answer
6k views

How can I resize my Lion partition to fill up the unused space on the drive?

My MacBook (Late 2007) has an 80GB hard drive. I used to have a 15GB Boot Camp partition, and deleted it at some point -- but I forgot to resize my Snow Leopard partition to fill the 15GB of free ...
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1answer
136 views

Can you run Disk Utility from bootable lion disk?

I've made a bootable lion disk by extracting the InstallESD.dmg from the lion installer app's package contents. - (Contents>SharedSupport>InstallESD.dmg) When booting from this disk, can you run disk ...
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7answers
13k views

What format for my external drive allows use with Mac and Windows?

How can I use my external hard drive on Mac OS so I can modify/edit files on both OS's: Mac and Windows? How should I format it?
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3answers
5k views

Unable to resize Lion partition

I decided to do a clean install of Lion on a new partition, then after copying my stuff removed the old one. I'm now stuck with 100~ GB of free space and a 20 GB partition that Disk Utility won't let ...
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1answer
782 views

Repairing Time Machine volume taking forever

Over 18 hours and counting, currently in the "Checking multi-linked directories" phase, but it's been there all night long. I see disk I/O, not a lot, but some. I assume its from the TM drive as the ...
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764 views

Migration Assistant fails to recognize a Time Machine disk (itself migrated using Disk Utility)

So I outgrow my Time Machine disk. I listen to the advice (repeated in multiple places) that one can simply use Disk Utility's Restore tab, select the old time machine disk as source and the new one ...
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4answers
31k views

How can I fix an Install Failed error while installing Lion?

I downloaded the new OS X Lion from the App store. I am running the latest Snow Leopard on my 2010 15" Macbook Pro. During the download, it somehow stopped while I was away from the keyboard. When I ...
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4answers
31k views

How can I resize a partition with Disk Utility?

I have 2 partitions, I reduced the size of one and want to expand the other to fill the now available space. How do I expand the Lion Partition into the empty grey space beneath Macintosh HD ...