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Questions tagged [disk-utility]

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

Disk Utility.app icon

Functions

The functions currently supported by Disk Utility include:

  • Creation, conversion, backup, compression and encryption of logical volume images from a wide range of formats read by Disk Utility to .dmg or, for CD/DVD images, .cdr
  • Mounting, unmounting and ejecting disk volumes (including both hard disks, removable media and disk volume images)
  • Enabling or disabling journaling
  • Verifying a disk's integrity, and repairing it if the disk is damaged (this will work for both Mac compatible format partitions, and FAT32 partitions with Microsoft Windows installed)
  • Erasing, formatting, partitioning and cloning disks
  • Secure deletion of free space or disk using a "zero out" data, a 7-pass DOD 5220-22 M standard, or a 35-pass Gutmann algorithm
  • Adding or changing partition table between Apple Partition Table, GUID Partition Table and master boot record (MBR)
  • Restoring volumes from Apple Software Restore (ASR) images
  • Checking the S.M.A.R.T. status of a hard disk

Disk Utility functions may also be accessed from the macOS command line with the diskutil and hdiutil commands.

Usage

This tag is for all questions related to Disk Utility.

It is suggested that if you are asking questions about Disk Utility, or possible bugs in a particular version of macOS, that you add the appropriate tag (such as or ), to allow users to easily distinguish when questions may or may not apply to their own circumstances.

Related Tags

There are several -related tags which allow you to specify your operating system version, such as:

2371 questions
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How do I get detailed SMART disk information on OS X (Mavericks or later)

I'm trying to get a detailed SMART status report on the drives in my Mac. I'm not talking about "Verified," I'm talking about the detailed report that's about 100 lines long listing all the vital statistics of the drive. Anyone know how to do this…
Mike Akers
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1 answer

No partition scheme option when erasing a USB disk in MacOS High Sierra?

In previous versions of MacOS, I recall that Disk Utility provided an option to select the partition scheme (GUID, MBR, or Apple). If I formatted the USB key without changing the scheme to MBR, I could not read it on a Windows machine. But now…
Richard Wеrеzaк
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55
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6 answers

Mount Ext4 on El Capitan

I recently installed OS X 10.11 on my Mac. I tried to read a SD card with an Ext4 partition which wasn't even shown in Disk Utility, although diskutil did show it as a Linux partition. I can't seem to mount the partition (the mount command seems to…
Milliways
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11 answers

External Hard Drive Won't Mount

I've searched and tried a lot of stuff but still can't get it to work. I was able to use my seagate HDD properly last week but now it doesn't mount. I tried plugging it to a PC & another mac, it works fine on both. The reasons could be Updating OS…
demiculus
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51
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2 answers

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?
user588
40
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4 answers

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 utility and then attempted to expand the main…
Dan
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39
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8 answers

Resizing or expanding a CoreStorage volume

I bought a new SSD with 750 GB and made two partitions: 600 GB and 150 GB. The smaller one was thought to be a Bootcamp partition one day, but to date it was just another unused partition. When I needed more space, I decided to merge these two…
Christian
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37
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9 answers

Unable to format / erase hard drive

I have an external HD that died on me a while ago and I'm trying to see if I can format / erase it to start using it again. The disk does not show up in Finder but I can see it in Disk Utility. When I try to erase it from there I get Disk Erase…
stef
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36
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7 answers

hdiutil convert/rsize resource temporarily unavailable

When trying to convert or resize a dmg image I get the error: hdiutil: convert failed Resource Temporarily Unavailable error or hdiutil: resize: failed. Resource temporarily unavailable (35). (hdiutil error code 35).
reto
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35
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11 answers

Unable to Resize Partitions

I have recently created a partition on my macbook air running OS X 10.9, and this was to run install another OS instance (Yes, OS X 10.10 Yosemite, but that is an aside to the query I have) on it. I got the partition running fine, with the OS…
Cory
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34
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7 answers

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 CCC is a file-level copy between disks. When I…
erotsppa
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34
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3 answers

USB Drive Will Not Mount, Not Listed in Disk Utilities, but Found In System Profiler

I have a Seagate FreeAgent Go drive with the optional docking station. I use it to keep files that I don't access on a regular basis and as a place to do "quick backups" of things like my Paperless library or my Lightroom Catalog. This morning, I…
Allan
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34
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2 answers

hdiutil: compact failed – Function not implemented

When compacting a sparse image with the hdiutil compact command, it fails with the message hdiutil: compact failed – Function not implemented.
KPM
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33
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3 answers

How to get the "securely erase" function of Disk Utility on El Capitan & Sierra

Up to Yosemite I regularly used Disk Utility with Erase > Security Options... > writes a single pass of zeros over the entire disk... as a simple method to fully check that a disk is fully safe before installing a new system or backup on it. For me…
dan
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33
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7 answers

Can't reformat SD card (Yosemite)

I have a 2 GB SD card that I can't reformat. It seems pretty corrupted. If I go into Disk Utility, I get these various error messages for each option: Repair Disk: Disk Utility can’t repair this disk. Erase (with Format "MS-DOS (FAT)"): Volume…
Bob
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