Cannot erase disk

Recently, I had to reformat my drive. Having done that, I began experiencing problems with connecting to the internet, and I have been told that all I could do was reformat again and hope for good.
The thing is, it will not reformat anymore. An error message pops up saying "could not unmount disk".
Any advice on how to overcome the problem?
Thanks!

Finnanigan:
Formatting, Partitioning Erasing a Hard Disk Drive
Warning! This procedure will destroy all data on your Hard Disk Drive. Be sure you have an up-to-date, tested backup of at least your Users folder and any third party applications you do not want to re-install before attempting this procedure.
• With computer shut down insert install disk in optical drive.
• Hit Power button and immediately after chime hold down the "C" key.
• Select language
• Go to the Utilities menu (Tiger and later) and launch Disk Utility.
• Select your HDD (manufacturer ID) in left side bar.
• Select Partition tab in main panel. (You are about to create a single partition volume.)
• Click on Options button
• Select Apple Partition Map (PPC Macs) or GUID Partition Table (Intel Macs)
• Click OK
• Select number of partition in pull-down menu above Volume diagram.
(Note 1: One partition is normally preferable for an internal HDD.)
• Type in name in Name field (usually Macintosh HD)
• Select Volume Format as Mac OS Extended (Journaled)
• Click Partition/Apply button at bottom of panel.
• Select Erase tab
• Select the sub-volume (indented) under Manufacturer ID (usually Macintosh HD).
• Check to be sure your Volume Name and Volume Format are correct.
• Click Erase button
• Quit Disk Utility.
cornelius

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My install of maverick failed as disk is damaged and cannot repaired. I tried to erase disk but got error that disk cannot be umounted. Please help! Thank you very much.

My install of maverick failed as disk is damaged and cannot repaired. I tried to erase disk but got error disk cannot be unmounted. Please help. What can i do? Thank you very much.

First have you got a backup of your data? If not try to get one now while you have some access to the drive. The drive is probably faulty and will need to be replaced, without the backup you risk losing the data.
Have you a bootable external USB drive with Mavericks on it, if so boot from that and try and repair or erase the drive and reinstall Mavericks.
If you don't have Mavericks on an external drive, boot from you Leopard DVD ( I am presumimg your profile is correct) and run Disk Utility from there, you may be able to erase the drive and reload Leopard. You can then install Mavericks. Even if all that works you will most likely need a new drive in the near future.

I have an old G3 I would like to donate, but I have forgotten my password and cannot erase the two partitions on my disk.

I have an old G3 I would like to donate, but I have forgotten my admin password and cannot erase the two partitions on my disk. I have the CD for 10.3.9 that one partition is running but when I boot from the CD, it wants to set up by connecting to the internet and I cannot connect on the old machine.
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Sure you can.
Drive Partition and Format
1. Boot from your OS X Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.
No password is required for this unless you set up a firmware password.

Cannot reinstall Tiger : installer stuck (cannot make disk bootable)

Good afternoon experts,
I am writing to you here as I have a problem with the Tiger installer which suddendly stops when trying to install on a prepartioned disk.
First, some background information : I have a 20' iMac Intel machine which I bought on February 06 (well designed machine, happy with it so far). The thing is, I have had serious crashes and lockups using the UB version of VLC (media player) which led me to hard reboot the machine several times. Despite the journaling on the disk, some of my filesystem was corrupted, seemingly beyond repair (some apps did not even boot, nothing happened when I plugged in an external disk, etc). Scanning for disk errors and permissions problems revealed that a lot of files had been damaged ("extended allocation" error) in both the system and in my applications.
As I did not know what to do (I should have asked first here whether it was possible to reinstall only parts of the OS using, maybe, a package manager), I synced my backups and went for a reinstall.
The thing is, the disk is already partitioned, as I also run Linux on the machine (updated firmware and repartitioned the disk w/ BootCamp; worked well). It contains, in that order : the hidden EFI partition (fat32), the macOSX HFS+ volume (where I want to install), Linux swap partition, HFS+ partition (for use w/ rEFIt, the EFI bootloader), and two Linux ext3 partitions.
The install starts fine (booting from the DVD which came with my machine), the macOSX volume is formatted but the installer just then stops. Looking at the logs, I can see that it is because it cannot make the volume bootable (this is what the error message says). Note that it correctly read the partition table/EFI partition scheme as it gives me the correct partition types I have presented above. Also note that I cannot do an "archive and install" procedure, seemingly because I have insufficient space (6GB free on the volume); the installer does not give me any choice. Finally, I can still boot into Linux holding the 'Alt' key and using the builtin volume chooser to start on the second HFS+ volume.
I am asking for help to you gurus, to know what to do here. I was think maybe something like using the shell to do a manual 'bless' would solve the issue; I would like however to be sure before proceeding. Otherwise, is there a manual installation procedure (as there is for instance on the Debian installer, allowing to skip/redo some install steps)?
Thanks for your help experts,
Vincent
PS: I am going to see whether I can collect the logs and post them here.

Hello back,
As I did not find a way to attach my logs, I am posting the most relevant parts of it here.
This is where the installer erases the volume and fails at make the disk bootable :
Jun 27 12:04:56 localhost : Preparing volume "Macintosh HD" for installation
Jun 27 12:04:56 localhost : Erasing volume for OS Install
Jun 27 12:04:56 localhost : Original Disk Layout
Jun 27 12:04:56 localhost : partition map from /dev/disk0:
Jun 27 12:04:56 localhost : #: type name size identifier mountpoint
Jun 27 12:04:56 localhost : 0: GUIDpartitionscheme *232GB disk0
Jun 27 12:04:56 localhost : 1: EFI 200MB disk0s1
Jun 27 12:04:56 localhost : 2: Apple_HFS Macintosh HD 70.0GB disk0s2 /Volumes/Macintosh HD
Jun 27 12:04:56 localhost : 3: Linux Swap 503MB disk0s3
Jun 27 12:04:56 localhost : 4: Microsoft Basic Data 18.6GB disk0s4
Jun 27 12:04:56 localhost : 5: Apple_HFS rEFIt 190MB disk0s5 /Volumes/rEFIt
Jun 27 12:04:56 localhost : 6: Microsoft Basic Data 143GB disk0s6
Jun 27 12:04:56 localhost : Preparing disk for erase
Jun 27 12:04:57 localhost : Erasing volume.
Jun 27 12:04:57 localhost : Erasing
Jun 27 12:04:58 localhost : Initialized /dev/rdisk0s2 as a 70 GB HFS Plus volume with a 8192k journal\n
Jun 27 12:04:59 localhost : Mounting Disk
Jun 27 12:04:59 localhost : Done erasing volume.
Jun 27 12:05:01 localhost : Final Disk Layout
Jun 27 12:05:01 localhost : partition map from /dev/disk0:
Jun 27 12:05:01 localhost : #: type name size identifier mountpoint
Jun 27 12:05:01 localhost : 0: GUIDpartitionscheme *232GB disk0
Jun 27 12:05:01 localhost : 1: EFI 200MB disk0s1
Jun 27 12:05:01 localhost : 2: Apple_HFS Macintosh HD 70.0GB disk0s2 /Volumes/Macintosh HD
Jun 27 12:05:01 localhost : 3: Linux Swap 503MB disk0s3
Jun 27 12:05:01 localhost : 4: Microsoft Basic Data 18.6GB disk0s4
Jun 27 12:05:01 localhost : 5: Apple_HFS rEFIt 190MB disk0s5 /Volumes/rEFIt
Jun 27 12:05:01 localhost : 6: Microsoft Basic Data 143GB disk0s6
Jun 27 12:05:01 localhost : Waiting for volume...
Jun 27 12:05:01 localhost : Configuring volume "Macintosh HD"
Jun 27 12:05:01 localhost : Preparing Disk for OS Install
Jun 27 12:05:01 localhost : Cannot make disk bootable at this stage.
Jun 27 12:05:01 localhost : partition map from /dev/disk0:
Jun 27 12:05:01 localhost : #: type name size identifier mountpoint
Jun 27 12:05:01 localhost : 0: GUIDpartitionscheme *232GB disk0
Jun 27 12:05:01 localhost : 1: EFI 200MB disk0s1
Jun 27 12:05:01 localhost : 2: Apple_HFS Macintosh HD 70.0GB disk0s2 /Volumes/Macintosh HD
Jun 27 12:05:01 localhost : 3: Linux Swap 503MB disk0s3
Jun 27 12:05:01 localhost : 4: Microsoft Basic Data 18.6GB disk0s4
Jun 27 12:05:01 localhost : 5: Apple_HFS rEFIt 190MB disk0s5 /Volumes/rEFIt
Jun 27 12:05:01 localhost : 6: Microsoft Basic Data 143GB disk0s6
Jun 27 12:05:01 localhost : Install failed: Couldn't prepare volume for installation.
Now, this is what Disk Utility reports of the volume. You can see that the partition scheme on the disk is the correct one :
Jun 27 12:09:05 localhost : Disk Utility started.\n
Jun 27 12:09:05 localhost : \n
Jun 27 12:09:18 localhost : Name : WDC WD2500JS-40NGB2 Media\n
Jun 27 12:09:18 localhost : Type : Disk\n
Jun 27 12:09:18 localhost : \n
Jun 27 12:09:18 localhost : Disk Identifier : disk0\n
Jun 27 12:09:18 localhost : Media Name : WDC WD2500JS-40NGB2 Media\n
Jun 27 12:09:18 localhost : Media Type : Generic\n
Jun 27 12:09:18 localhost : Connection Bus : SATA\n
Jun 27 12:09:18 localhost : Connection Type : Internal\n
Jun 27 12:09:18 localhost : Partition Type : GUIDpartitionscheme\n
Jun 27 12:09:18 localhost : Device Tree : /PCI0@0/SATA@1F,2/@0:0\n
Jun 27 12:09:18 localhost : Writable : Yes\n
Jun 27 12:09:18 localhost : Ejectable : No\n
Jun 27 12:09:18 localhost : Mac OS 9 Drivers Installed : No\n
Jun 27 12:09:18 localhost : Location : Internal\n
Jun 27 12:09:18 localhost : Total Capacity : 232.9 GB (250,059,350,016 Bytes)\n
Jun 27 12:09:18 localhost : S.M.A.R.T. Status : Verified\n
Jun 27 12:09:18 localhost : Disk Number : 0\n
Jun 27 12:09:18 localhost : Partition Number : 0\n

IMac cannot erase partition in recovery mode

Hi,
I bought an iMac Retina 5K in Dec. 2014. I am using OS X 10.10.1, 3T fusion drive. Now I want to erase and re-install OS X. However, when I enter the recovery mode, the os does not let me erase the partition. After first attempt of erase, all the selection and button became gray and un-selectable.
I want do know if it is normal that I cannot erase for the new model. How can I erase and re-install, or restore to factory state.
Thank you so much!

I just returned a new iMac with a fusion drive after one week (many power related problems) - I also had a problem erasing, but finally managed by choosing the actual drive, not the top most entry in the Disk Utility window. I no longer have it now to do a screenshot, but I am referring to the actual hard drive like this one:
As to not being able to choose the top entry - I believe this is the behavior because of the fusion drive/SSD which you have no control over.

What is the best way to recycle 2010 MacBook? Also, it is completely dead and cannot erase hard drive.

What is the best way to recycle old 2010 MacBook? Also, it is completely dead and I cannot erase hard drive.

Depending on where you are located, country, region, etc, you may have options should
you wish to have it professionally restored or repaired to function properly again...
Even an Apple Store with Genius bar could, in several locations, give the product a look
and perhaps be able to diagnose the underlying issues. However that varies with the
degree of failed components and what is really wrong with it. A battery and a new HDD
could be all that's wrong with it. A diagnostic is often free, even on out-of-warranty Mac
at the Apple Store genius bar; an appointment is advised.
However if you only wanted someone to extract the hard disk drive and attach it to
a 'universal USB drive adapter kit' so at to try and access any readable files on it,
that is something that could be done at an Apple Authorized service provider; as
some of them may even have a section of resale products such as this adapter kit.
An example of this kind of kit includes wires, adapter parts, & a separate power supply
so it can be used to run the hard drive's electronics. This is not intended for permanent
use, but works like a set of patch cables to access the bare drive without an enclosure.
https://www.ifixit.com/Store/Mac/Universal-Drive-Adapter/IF107-108-1
Another kit example says it'd work with almost any HDD or SSD of several build types:
http://eshop.macsales.com/item/NewerTech/U3NVSPATA/
Companies that specialize in restoring Apple portable computers can give you an estimate
on a repair and the good ones can do that without a fee; they will not start a repair after they
see the computer until you get the estimate, and approve of the repair. If other items are
found to be of interest requiring other work or parts, they will also contact you, again before
continuing. One of these kinds of companies I know about (half a hemisphere away) is in
the eastern US, and worth inquiring of even if you are overseas. wegenermedia.com.
While I have no connection with any of these products or service suggestions, they do have
some variety of good reputation (ifixit.com has DIY repair guides; macsales has parts, etc.)
in standing, among many Mac users across a section of the planet...
Any concerns about the data on the hard disk drive should be able to be answered by a
local Apple independent; they also should have the universal USB drive adapter locally.
Not sure if I answered your inquiry, but there are different ways of approaching this matter.
Good luck & happy computing!
edited

Cannot erase Macbook Air SSD

Hi,
I'm having a Macbook Air with 128GB SSD and 4GB RAM with OS X Mavericks. I was using my Mac normally but suddenly chrome got stuck. So I held down the power button and shut down the Mac. When I switched my Mac on again, it wont start.
I tried to repair my SSD using diskutility from Recovery Partition. But it says something is wrong with my Partition Map and that I have to erase and reinstall OS X. But I cannot erase my SSD. The progress bar gets stuck at 50%.
When I used command line diskutil eraseDisk, it shows Waiting for disks to reappear and is stuck at 50%.
Is it a problem with my SSD. If yes, will I be eligible for Warranty?

Is this MBA functional? Will it boot to an OSX?
You may try OPTION+COMMAND+R which would install the original OSX.
You could get an appropriate enclosure for the SSD and connect it to a working Mac and erase it that way.
Ciao.

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In my iPhone 4, there are some files I would like to, but cannot erase, probably because I accidentally placed them in an incompatible App.
I understand that files belonging to a specific App in iPhone (or my iPad Mini II as a matter of fact) must be erased from within the App itself and not from iTunes.
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Thanks in advance.

In Terminal use the umount command. You will need to know the identifier of the disk you're trying to unmount. The command will look something like 'umount /dev/disk1'.

Cannot erase software program in Windows 7 64--bit

Greetings to all, I have a Windows 7 64--bit with all the updates on a W520. I had installed Libre Office 3.5 on May 14,2012. I have wasnted ot upgrade to the latest version and i cannot. I cannot erase the softwarem, the response kthat I get is that all
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Try starting the computer in Safe Mode. See if you can remove the program while in Safe Mode. Following that, reboot normally.
http://www.pcworld.com/article/240802/how_to_enable_safe_mode_in_windows_7.html
ThinkPad: T530 / X1 Gen 2 / Helix - Yoga: Tablet 2 Pro (Win) / Yoga 3 Pro
If you find a post helpful and it answers your question, please click the "Accept As Solution" button.
Lenovo Advocate ~ I am not employed by Lenovo or Microsoft. I am a volunteer.
Microsoft MVP - Consumer Security
SpywareHammer

I have deleted my private folder and do not have enough space to reinstall my operating system. How can i transfer files from my hard drive to an USB drive to free up space when the operating system isn't working. or do i need to erase disk?

i have deleted my private folder and do not have enough space to reinstall my operating system. How can i transfer files from my hard drive to an USB drive to free up space when the operating system isn't working. or do i need to erase disk through disk utilities without erasing data (but will it delete my programs such as photoshop, office, creative suite?

Connect the computer to another Mac and put it in FireWire Target Disk mode, or use the Disk Utility to clone the drive or image specific folders with the USB drive as the target. After you've copied off everything you want, you'll likely need to erase the drive and reinstall the applications.
(69695)

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I want to use Disk Utility to erase my HDD on MacBook Pro. BUT the Erase disk is greyed out. I checked user account and unlocked the padlock for my Admin account. What next please?

Remember to press the 'C' key to boot on the Snow Leopard disk (or set the boot disk from Preferences -> Startup disk)...
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boot up the machine and press R to get to the recovery mode.
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Place your phone in DFU mode (search Google) and restore

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Cannot erase disk

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