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

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7
votes
4answers
9k views

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 ...
3
votes
4answers
1k 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
2answers
2k views

What are the purposes and safety to enable the hidden debug menu in Disk Utility?

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: ...
13
votes
7answers
54k views

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 ...
7
votes
4answers
41k 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 ...
4
votes
1answer
1k views

Can't make more than two partitions

I want to multiboot my MacBook Pro, I'm trying to make partitions but in Disk Utility I can't make my partitions, only can divide by 2? Why? It's a normal SSD not a fusion drive (SSD+HD). Now I'm ...
8
votes
2answers
5k 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 ...
5
votes
2answers
22k 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
19k 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 ...
3
votes
2answers
1k views

I think I messed up the Fusion Drive on my 1TB iMac (with BootCamp)

this is a somewhat similar post to this one (Can't create partition on free space with Disk Utility) but not quite... It started with me creating a BootCamp partition (around 145 GB) for Windows ...
3
votes
4answers
12k views

Recovering data off of a dead hard drive

My hard drive died in my macbook and it no longer will start up. It will not mount in an external enclosure but disk utility is still reading that the hard drive is there, and I tried to repair disk ...
24
votes
3answers
57k 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 ...
6
votes
1answer
16k views

Create new partition in unallocated space with diskutil

I have deleted the first partition on my external HD such that it now has 100GB of free space at the beginning of the partition. I'd like to reclaim that space, but Disk Utility doesn't let me create ...
2
votes
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 ...
9
votes
1answer
377 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, ...
5
votes
1answer
6k 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 ...
1
vote
2answers
2k views

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 ...
1
vote
2answers
319 views

What's the tool that can do some actions when a file is copied?

I use Cmd+L to make a alias, and the alias has "alia" appended to the original file name. I move the link to a directory, then remove the "alias" part manually. Is there a tool that can do this kind ...
6
votes
2answers
3k 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, ...
2
votes
4answers
16k views

Restore Macintosh HD to its original partition configuration

I seem to have badly botched a Boot Camp installation of Windows 8.1. I used Boot Camp Assistant to create a 200 GB BOOTCAMP partition on my 1 TB Fusion Drive. I then rebooted and failed to install ...
1
vote
3answers
530 views

For bad and/or marginal blocks on hard disks, can anything be more effective than a single pass of zeros?

There's a good discussion in Apple Support Communities – Disk Utility: for bad blocks on hard disks, are seven overwrites any more effective than a single pass of zeros? (2011-04-21) A highlight: ...
1
vote
1answer
7k 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 ...
2
votes
1answer
3k views

Resizing dual boot partitions in Yosemite

I have a dual boot Macbook Air with Yosemite and Ubuntu. I would like more space on my Ubuntu partition and need to therefore reduce the size of the Mac partition. I assume this will cause some damage ...
2
votes
3answers
283 views

Completely erased my Leopard machine from another computer, how do I install an OS on it?

I started up my computer in Target Disk Mode and erased it from a friends Mac thinking that I could then install Mountain Lion without installing Snow Leopard. Do I have any way of getting my machine ...
2
votes
2answers
3k views

Disk diagnostic and repair utility for Mac that works with all kinds of storage devices?

There are some nice and useful utilities for testing disks for bad blocks like MHDD, Victoria, HITACHI Drive Feature Tool etc. But these utilities have some limitations. For example, MHDD is the best ...
1
vote
3answers
485 views

Unable to increase partition size with subsequent blocking partition

I can't make my main Macintosh HD partition bigger. It's limited by the partition in the middle, which seems to be frozen, I can't move it down to make space for my main partition. Also I can't seem ...
1
vote
2answers
3k views

Remove “Windows” Entry from Mac Boot Loader

Background A while back, I installed Windows 8 on my MacBook Air (mid 2013 model) using Bootcamp. It never really worked, (it would freeze all the time, the WiFi would cut in and out, etc.) so I got ...
1
vote
2answers
30k views

What are next steps when fsck reports “could not be repaired after 3 attempts”?

My Mac Book Pro 13.-" doesn´t get past the grey booting screen with the apple and the spinning wheel (The loading bar appears but when it´s done nothing happens) I have 220 GB in one single ...
1
vote
3answers
4k views

I have 21.5GB free. Why won't my MacBook Air 2010 let me use Boot Camp?

I'm trying to install Windows 7 on my MBA, 2010. I open up Boot Camp and attempt to use it, but after the first screen it comes up with an error saying it can't install unless theirs 10GB of free ...
11
votes
6answers
32k 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 ...
7
votes
3answers
12k 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 ...
2
votes
2answers
2k views

Can't see new SSD when connected via internal SATA port

I just bought a new Samsung SSD 830 and installed it my 13" MacBook Pro (Mid 2010) in the hard disk bay, replacing the drive that was there (I actually have a second drive in the optical drive's ...
8
votes
2answers
39k 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 ...
6
votes
4answers
7k 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 ...
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
468 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
352 views

How to kill the popup in OS X when a disk can't be ejected

With ZFS-OSX, sometimes when I try to force eject my HDD and it's failing, the following popup appears on my screen – floating on the top with all the buttons grayed out – and no possibility to close ...
3
votes
3answers
2k views

Why does my 3TB Seagate HD keep formatting as a Logical Volume Group

This is really annoying. I have a brand new Seagate 3TB 7200 RPM hard drive that I am trying to format/partition in Disk Utility. Every time I change any settings or erase the drive, it changes it to ...
2
votes
3answers
8k views

How can I tell if my iMac's hard drive is dying?

A couple of days ago, my three-year-old iMac locked up. When I rebooted it, it only displayed a folder icon with a flashing question mark. After a couple more reboot attempts, it booted. I ran Disk ...
0
votes
1answer
83 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 ...
5
votes
2answers
19k views

how can I delete a partition (coreStorage logical volume?) from the Terminal?

I finally understood why Disk Utility will not change the partitions on my HDD, even though I added the most recent one myself (maybe significant: to test Yosemite DP) with it. Now I see it says it ...
2
votes
1answer
6k views

MacPro Hard Drive 3 TB or Larger formatted to Logical Volume Group by Disk Utility

I have an Intel MacPro in which I recently installed a new internal 3TB hard disk. I attempted to format it in Disk Utility using the standard GUID partition map and encountered a strange problem. ...
2
votes
2answers
2k views

Which format for external disk for performance?

I'm using OS X Mavericks and just got a new external hard disk. I don't need to share it with a PC (so no need for FAT) but I do want it to have better I/O performance. I'm a bit confused by the ...
2
votes
3answers
1k views

Understanding how safe boot fixed a boot problem

Background My friend asked me to look at her early 2011 Mac Mini with OS X 10.8.3. She said that: she installed software updates she couldn't remember which updates were installed when the Mac ...
2
votes
4answers
6k views

How to install Mountain Lion on a disk that cannot be formatted in recovery mode?

I'm trying to do a clean install of Mountain Lion but I'm not being able to format my partition. I previously had Lion, encrypted the disk, then upgraded to Mountain Lion, then booted into recovery ...
1
vote
5answers
20k views

How do I fix my SSD after installing Yosemite and Enabling TRIM? No boot & can't erase

I recently upgraded to Yosemite, enabled FileVault and foolishly enabled TRIM (had no idea it wasn't supported). Upon restart, my machine gets the grey screen with the crossed-out circle of death. ...
0
votes
1answer
904 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 ...
10
votes
1answer
11k 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 ...
8
votes
9answers
28k 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 ...
4
votes
1answer
244 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 ...