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Question: Q: Disk Utility: Erase process has failed Hi, I have just bought a new Seagate Expansion Drive, and it was formatted as a windows drive so I went to Disk Utility and erase/formatted it to OS X Extended (Journaled).
Ok, so short story is I tried to install windows 10 on a flash drive of 120gb, and accidently installed it over the main SSD of my 120gb MacBook Pro.
This of course means that through the Windows installation reformatted the main partition of my APPLE SSD to NTFS. Not being able to boots OSX as it's no longer there, I decided to boot OSX Utilities, and attempt to reinstall OSX.
When doing so, the main disk to which I wanted to reinstall OSX to said it was locked. So I went back to the Disk Utility, found the main drive (which said it was in NTFS) and went to erase it as Mac OS Extended.
However that doesn't appear to have worked. All I can see is :121.33GB APPLE SSD[grayed out] >disk0s1 - 471.9MB[grayed out] >disk0s3 - 16.8MB[grayed out] >disk0s4 - 120.74GB
And now, when I go to reinstall OSX again, there is no drive to select in which to install it.
Yet when I select the 'disk0s4' and try to erase as Mac OS Extended, I am confronted with the message:
'Volume Erase failedVolume Erase failed with the errorMediaKit reports not enough space on device for requested operation.'
MY SITUATION means that I have a MacBook Pro, that can only boot Windows from the internal SSD (I assume it is on the disk0s4).I realise I probably can't restore my Mac as it was, but I'm not bothered. I just want to get rid of Windows and load back OSX onto the main drive, like when I bought it.
ne14azane14aza
2 Answers
Don't try to format the existing partitions. Completely erase the drive and start fresh.
See here, under 'Erasing your startup disk if necessary.'
In the instructions, notice the drive is selected (APPLE SSD SM0256F Media) for erase, not the partition (Macintosh HD).
AppleoddityAppleoddity
If you have internet available you can restart and hold command-option-r.
It may prompt you to choose the wifi at the next screen (spinning globe instead of the Apple logo, wifi pop up menu underneath). Choose, enter password if needed and it should take a few minutes to boot to Internet Recovery. If using Ethernet then you won't see this.
This will be the original version your computer shipped with, mind you. Otherwise it will be identical to the recovery disk it sounded like you were already booted from. If you were booted from it and you tried to repartition it wouldn't have let you because you're actually booted to a partition on the SSD still.
From there you can just try using disk utility, highlight the drive on the left (not any of the partitions, they'll be indented under the drive) and on the right side go to the Partition tab. Change the number of partitions from Current to 1. Near the bottom of that section is an Options button, click that and change the partition map to GPT (or GUID, whichever shows is the one). Click Ok so you're on the previous window, click Partition to remap the drive as GPT, which will erase it completely.
If that's successful then I'm guessing your next step might be reinstalling OS X? If so then quit Disk Utility and choose Reinstall OS X.
If the whole disk utility erase didn't work then let's try using diskutil from the terminal.
Assuming you're back on the main screen (after quitting disk utility), go to the Utilities menu at the top and choose Terminal. Let's be sure which disk we're dealing with exactly:
You'll see your drive (labeled physical) and a bunch of virtual mounted drives from the network boot. Let's assume the drive we want is disk0. The other partitions don't matter from what you said, so let's remap:
This will repartition it as GPT with a single partition named HardDriveName and use all available space for it.
From there quit terminal and at that main screen once more just run Reinstall OS X. The installer once doing its thing will take care of any boot loader partitions and boot entries and get everything back to factory for you.
Cory TCory T
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The user often experiences a problem, while handling some of the Macs, when they are not allowed to repair permissions or directory in Disk Utility. They are unable to erase or partition the drive. Even the Network deployment tools like Apple’s Netinstall service or the DeployStudio fails, on account of this error. The error, which is thrown, is the:
Disc erase failed couldn’t unmount disc.’
or
‘Disk Erase failed with the error: Couldn’t unmount disk.’
The error occurs in such situations like formatting Mac as well as partitioning and verification and repairing of Mac disk.
Causes
The reason for this error is the modification of the boot drive, or it is being used by some other process or application. If the internal drive is causing the issue because the OS X Recovery exists as a partition on the physical disk, unable to modify or unmount the internal drive, then the preference must be given to a network drive or an external drive.
Solution
There are many solutions when the user faces these problems.
Using an external drive or OS X Recovery for the starting up of the Mac from another bootable drive. Disk Utility can be run from the external drive. The version of the OS X does not matter, by at least must be 10.7, 10.8 and 10.9. The one and only requirement are that Disk Utility must reside on the drive.
There are three means of resolution of the problem. These are:
(1) Fixing with Partition Manager
If the OS X is denying you to format, erase and repair the Mac hard drive or a volume due to the Couldn’t Unmount Disk’ Error then use Partition Manager Application to format the hard drive with Mac OS X Extended Journaled file system. Formatting the hard drive or partition scheme will recreate a new HFS file structure on the hard drive, which will be free from cryptic errors. Further, the disk manager utility will allow the user to create, resize, add partitions on the hard drive with HFS, FAT or NTFS file systems.
(2) Fixing with USB Boot Drive
This is the most recommended method to repair the error. Any OS X boot drive is needed to complete the task. But, the important point to remember is that the installer or the recovery drive must reside in the drive, separate from the primary boot disk with the installed OS on it.
The following steps can do the fixing:
- The USB boot drive is attached to the Mac, and the system is rebooted
- The OPTION key is held during the booting and then the attached boot drive is selected
- Disk Utility is accessed through the Boot menu. It is the Utilities Menu for the Installer Disk
- Verification of the Disk is done with the “First Aid.”
- The repair is done
- The original task which was halted due to the above error was performed again
The above steps offer a resolution of the problem. The errors could have been unresolvable without a boot drive. Therefore, a bootable thumb drive was a good option. For the older Mac OS X like 10.6 or earlier, the opportunity lies in a SuperDrive and a bootable DVD, and this can also offer the same resolution.
(3) Fixing With the Recovery Partition
The above error may also be triggered due to first Aid or while formatting a non-boot partition. In this case, a resolution of the problem occurs with the Recovery Partition, which comes with all the newer versions of the Mac OS X. However, this is not applicable for the modification of the boot disk with the help of partitions or formatting. Then the resolution lies in the previous method. Otherwise, we follow the steps:
- The Mac is rebooted, with the OPTION key being held down and the Recovery Partition is chosen
- The Disk Utility is chosen from the Boot Menu
- Verification and repairing the disk is done with the “First Aid.”
or
- “Erase” is used for the disk formatting
This will not work with the disk that is throwing the error is the same as the primary boot partition. The solution lies only in using a separate USB drive for fixing the error.
External USB Drive not Mounting on Mac?
Device failure may happen any time without warning. The loyal external hard drive may not show up or mount in Finder. Imagine how will one access the videos, documents like spreadsheets etc. or thousands of photos if the external drive doesn’t mount on Mac?
Thankfully, advanced software such as Stellar Data Recovery Professional for Mac can help you recover data from an unmounted external hard drive.
Thankfully, advanced software such as Stellar Data Recovery Professional for Mac can help you recover data from an unmounted external hard drive.
Stellar Data Recovery Professional supports the recovery of files from an external hard drive on macOS Mojave, High Sierra and other macOS/OS X variants. Further, it provides support for data recovery on APFS, HFS, HFS+, NTFS, FAT and ex-FAT external hard drives. Once you have activated the Mac recovery tool you can recover as many numbers of files from any given external drive or SSD.