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

learn more… | top users | synonyms

16
votes
3answers
37k 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 ...
13
votes
2answers
1k views

What is the difference between a “sparse disk image” and a “sparse bundle disk image”?

What are the differences between sparse and sparse bundle disk images?
11
votes
2answers
25k views

How can I delete everything from my MacBook Pro before selling it?

I have a Mac that runs Snow Leopard and I intend to upgrade it to Mountain Lion and sell it on ebay. However, I only have one hard-drive, and I'm sure I can't use something in my OS to delete my OS ...
10
votes
7answers
11k 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?
10
votes
1answer
3k views

Can Disk Utility format an SD card with FAT32?

In the pulldown for "Format", there are only the following options (other than various Mac OS Extended variations): MS-DOS (FAT) and ExFAT.
9
votes
1answer
302 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, ...
8
votes
6answers
16k views

What is the best way to clone a disk between two Macs?

What is the best way to clone a disk between two Macs? I ask this every couple years or so and every time I get the same answer. "Use Carbon Copy Cloner", they say. But the unfortunate fact is that ...
8
votes
2answers
6k views

How do I resize OS X main partition when I already have other BootCamp partitions?

Short story: partition resizing using Disk Utility fails because MediaKit reports no such partition when I try to shrink it. I also tried the same while booting from the DVD, same result. Details: ...
8
votes
9answers
13k 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 ...
7
votes
2answers
4k views

How to fix Disk Utility, About This Mac, and Finder that disagree on hard drive space usage?

Has anyone seen this issue and know how to fix it? Look at the free space reported by running "Get Info" on my hard drive (Macintosh HD) in the Finder, "About This Mac" from the Apple Menu, and Disk ...
7
votes
2answers
645 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 ...
6
votes
4answers
3k views

What are the sector sizes on Mac OS X?

I read on the HFS Plus Wikipedia page that the default sector size on a Mac is 512 b. However, I also read that Macs support 4kb sectors. How can I determine which I have, 512 b or 4 kb sectors? I ...
6
votes
4answers
28k 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 ...
6
votes
1answer
395 views

How do I clone a hard disk excluding some directories?

In preparation for Lion, I want to make a bootable clone of my system to an external harddisk. I use TimeMachine, but I want to be sure I have a running backup. Of course, there is much stuff on my ...
6
votes
2answers
1k views

What terminal command or program can list an SSD's Power On Hours?

I'm looking to script using the unix shell the retrieval of SSD (and HDD) data that disk utility shows in the information window. I'm immediately interested in the Power On Hours and Power Cycle, ...
6
votes
3answers
4k views

Creating boot disk for Windows 7 on MacBook Pro

EDIT: I gave in and burned the DVD from a windows PC and I was able to install Windows on my MacBook Pro with Bootcamp. Sorry, that I don't have a satisfying solution. My goal is to install Windows 7 ...
5
votes
1answer
459 views

External Hard disk 500 GB free but can't copy 8 GB data

I have WD external hard disk, which was working fine. Its MS-DOS formatted. I have downloaded a file in .mkv, which works fine, and isn't corrupted. Upon copying the 8 gb file, it says "The file is ...
5
votes
4answers
5k 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. ...
5
votes
1answer
1k views

How can I tell which volume the operating system is on?

I'll admit that I am kind of rolling multiple questions in to one here so please forgive me and try not to knock me for it. I am new to Mac but I'm trying to port one of my Java applications to OS X. ...
5
votes
1answer
3k views

What kind of encryption does Mac OS X Extended (Journaled, Encrptyed) use?

Since my primary hard disk is encrypted with FileVault2, I also wanted my backup drive to be encrypted. I plugged in my external drive, brought up Disk Utility, and went to erase/format the disk. I ...
5
votes
1answer
5k views

Disk Utility won't Unmount HD for formatting

I have two internal drives in my 27" iMac (10.8.5). An SSD system disk and a 1TB SATA drive. The HDD has been acting up recently, very slow performance, bad behavior etc. Tech Tool Pro and Disk ...
5
votes
1answer
541 views

Presence of a Linux partition causes FileVault2 setup to fail

I'm currently dual booting Mountain Lion and Ubuntu 12.04 on a rMBP. Everything works fine, but enabling FileVault fails with the error message: "Some information was unavailable during an internal ...
5
votes
1answer
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 ...
5
votes
1answer
227 views

Unable to format pendrive, diskutil error

When I insert my USB Pendrive in my iMac i see this message: I tried to format it both with DiskUtility and with diskutil command in terminal but I get this error: iMac:~ User$ diskutil eraseVolume ...
4
votes
3answers
5k views

“Warning: SUID file has been modified and will not be repaired” after repairing disk permissions

Warning: SUID file “System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent” has been modified and will not be repaired. I keep getting this after running Disk Utility ...
4
votes
1answer
5k views

Can't ever remove partition?

Running Mountain Lion. I added a partition with Disk Utility and then had second thoughts about it. I'd like to remove the partition i created, MacSSD2 and hand over its space back to MacSSD. As you ...
4
votes
2answers
319 views

How to checksum for a DVD under Panther?

I'm helping a friend checking if a DVD was burned properly but he's saying that under Panther there's no Images menu in Disk Utility.
4
votes
2answers
2k 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 ...
4
votes
3answers
8k 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 ...
4
votes
2answers
14k views

installation stuck in a loop due to damaged HD

Right off the bat I'll admit it was stupid to jump into trying to install a new version of OS X to the only partition without having taken adequate precautions (no backups or recovery disks), but ...
4
votes
2answers
3k views

What are “dmgpart” files and what tools can create, merge, or manage them?

I downloaded something that came as three large files: One was a *.dmg (a disk image file, which I expected) and two more were *.dmgpart files, which I haven't happened to see before – I never ...
4
votes
2answers
16k views

How do I change a disk partition map scheme from MBR to GUID Partitions Table?

I just finished the huge download of Mac OS X Lion, started the installer, and now I have a problem. The installer says that I must have the GUID-Partitions Table Scheme. The problem is that when I ...
4
votes
2answers
2k views

Optimal method to test an external hard drive?

I've got an HFS+ formatted external drive that is starting to act a bit funny, mainly causing my mac mini (finder) to freeze up on occassion when accessing it. Fearing imminent failure, what is the ...
4
votes
2answers
493 views

How can I make my computer believe a disk image is a hardware disk?

I'm trying to do some research on TimeMachine right now. I don't want to purchase an external hard drive, just to learn about some software, and so I'd like to be able to tinker with the settings, by ...
4
votes
2answers
392 views

Software update never completes

I have an eMac (PPC G4) with 512 MB RAM, running 10.5.8. When I run Software Update, the "Checking for new software..." process never completes. I have tried deleting my ...
4
votes
1answer
2k views

Can I partition an iPod (nano, classic, shuffle) for use as a flash drive?

I have made an iPod nano appear as a flash drive by going to iTunes and checking "Enable disk use." However, I am short of a large enough USB key to hold a bootable Windows 8 installer for use by Boot ...
4
votes
2answers
3k views

Why does OS X now think I have two partitions on my external USB drive (plus random connection issue)?

I have an external USB drive that I have plugged into a USB hub, which gets unplugged from my computer about once a day. Most of the time I remember to unmount the drive before disconnecting so that ...
4
votes
3answers
1k views

How to create a bootable USB drive for Disk Utility?

Disk Utility says my boot drive need repair. Unfortunately my DVD drive is toast, so I can't boot from the install DVD and make the repair. Is there a way I can create a bootable USB drive and ...
4
votes
2answers
2k views

How do I recover an “invisible” OS X boot option in BootCamp (running on a 2013 MBA)?

Summary Unable to boot into the OS X partition of a 2013 MBA which dual-boots OS X and Windows 8 via BootCamp. Could "Repairing Disk" via "Disk Utility" damage the working Windows 8 partition? What ...
4
votes
1answer
65 views

Disk Utility does not show OK message after Verify Disk

Rebooted and Verified Disk twice. There is no OK message and stops here: Is it a new behaviour under Mavericks, or something wrong? How can I fix it?
4
votes
1answer
151 views

How to restore Applications & Files from HD Backup (Migration Asst won't read it)

I recently had a problem with my MBP which wouldn't start up. After the chime it would shut down. I started using ⌘ cmd+R and ran Disk Utility. Had issues with my boot partition but no issues on my ...
3
votes
2answers
2k 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 ...
3
votes
2answers
1k 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.
3
votes
2answers
28k 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 ...
3
votes
3answers
422 views

Copying Time Machine backup, destination takes more than original size, are hardlinks being expanded?

I'm copying the backup folder of Time Machine, but it's taking too long, the backup is 90GB and the copy already reports 160GB and there's 60% to go yet, so I suspect it's copying hardlinks as ...
3
votes
1answer
2k views

How do I erase an encrypted TimeMachine drive on Mountain Lion if I've forgotten the password?

My question is similar to this question. I have a USB drive that contains an old encrypted backup. I don't remember the password and don't care about loosing the backup - I just want to be able to use ...
3
votes
4answers
914 views

What techniques for disk, volume and file system management are possible with OS X, but troublesome within Disk Utility?

In the past, Disk Utility was the best starting point for the vast majority of disk-related tasks. As technologies within (or possible with) OS X have developed – without equal development of Disk ...
3
votes
3answers
1k views

Why does RAID 1 “Mirroring not provide performance improvements”?

I have always used Software RAIDs, either Apple-provided, or via SoftRAID, etc. I am about to re-zhuzh my arrays and decided to do a little research beforehand… and On Apple's site, there is a ...
3
votes
1answer
1k views

JDiskReport is damaged, can't be opened

I have tried downloading and running JDiskReport 1.4 a few times now, and after unzipping it and clicking on the executable I get the message: "JDiskReport" is damaged and can't be opened. You ...
3
votes
2answers
3k views

Format SD card with FAT and custom file allocation unit size

I'm using Maverick (a offline mapping application) on my Android device which has thousands of files in the tile cache with a size of 168 byte. The SD card is formatted with a file allocation unit ...