Error "cannot unmount disk"

I tried to erase+ reformat my Seagate HD for Macs but got the error "cannot unmount disk." Does anyone know what this means and how to fix it?
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'.

Similar Messages

  • Cannot unmount disk

    I am trying to install OS X 10.4.6 on an iBook.
    I am installing from a DVD copy made by the local apple store.
    The "Checking your installation DVD" part completes without errors.
    During the install it stops and says:
    BomFatalError - cpio read error: bad file format
    Install failed: some files for BSD may not have been written correctly
    I've tried this several times, always with the same error.
    In the Disk Utility - First Aid tab, I tried Verify Disk and Repair disk, both which fail with "Could not unmount disk"
    I also tried Verify Disk Permission and Repair Disk Permissions, both of which complete successfully.
    Then I tried to erase the disk (1 pass), and it says:
    Zero Disk failed with error
    Could not unmount disk.
    What else can I do?
    iBook
    PowerBook4.3
    PowerPC 750(1.12)
    1 cpu
    700Mhz
    640mb ram

    Here's the readme...sorry, don't know what we're looking for, so the whole thing:
    Read Before You Install Mac OS X
    Read this document before you install Mac OS X. It includes information about supported computers, system requirements, and installing Mac OS X.
    For more information about Mac OS X, visit this website: • www.apple.com/macosx/
    For the latest information about using Mac OS X, connect to the Internet and open Mac Help. To open Mac Help, click the Help menu in the Finder and choose Mac Help.
    For information about the support available for this product, see the AppleCare Software Services and Support Guide included with Mac OS X.
    System requirements
    You must have a Macintosh computer with: • a PowerPC G3, G4, or G5 processor • a DVD drive • built-in FireWire
    • at least 256 MB of RAM • a built-in display or a display connected to an Apple-supplied video card supported
    by your computer • at least 3 GB of disk space available, or 4 GB if you install the developer tools
    If you see a message in the Installer that you do not have enough disk space to install Mac OS X, you can deselect items to save space. To deselect items, click Custom Install in the Easy Install panel.
    Updating your computer’s firmware
    You may need to update your computer’s firmware. It’s best to update the firmware before installing Mac OS X. If you haven’t started the Mac OS X Installer, check the Apple Software Updates website to see if there are any firmware updates for your computer:
    • www.apple.com/support/downloads/
    If you don’t do this, you may see a message that you need to update your computer’s firmware when you start the Installer. To update the firmware, you will need to quit the Installer and restart your computer using your current startup disk, then check the Software Updates website.
    If you have problems with your computer after installing this version of Mac OS X, you might need to update the firmware even though you did not see a message when you installed the software. Check the Software Updates website for recent firmware updates for your computer.
    Starting installation
    To start installing Mac OS X, insert the Mac OS X Install DVD and double-click the Install Mac OS X icon:
    You can also start installing Mac OS X by inserting the Install DVD and restarting your computer while holding down the C key, or by selecting the Install DVD as your startup disk using Startup Disk preferences.
    Quitting the Installer
    If you need to quit the Installer before you click Install in the Easy Install or Custom Install pane, choose Quit Installer from the Installer application menu, then click Startup Disk to select a startup disk for your computer.
    If you have already clicked Install, wait until installation finishes.
    Advice about hardware compatibility Installing on a Power Macintosh G3 (Blue and White)
    If you have a Power Macintosh G3 (Blue and White) that came with an Apple SCSI hard disk, do not choose UNIX File System (UFS) as the format for the destination disk.
    Installing on a computer with a third-party SCSI card
    If you have a third-party SCSI card installed in your computer and you cannot start up Mac OS X, attach a disk drive or terminator to one of the card’s ports. If you continue to have problems, try removing the card. Contact the manufacturer of the card for more information about using the card with Mac OS X.
    Installing on a computer with a third-party video card
    If you have a third-party video card installed in your computer, you may need to remove it before you install Mac OS X. Contact the manufacturer of the card for more information about using the card with Mac OS X.
    Advice about installing Mac OS X Erasing and formatting your disk
    When you install Mac OS X, you can erase the destination disk you select. In the “Select a Destination” pane of the Installer, click the Options button. Select Erase and Install then choose a format. In most cases, choose Mac OS Extended (Journaled).
    Important Do not choose UNIX File System (UFS) unless you need to work with this format. If you choose UFS, Mac OS 9 and all Mac OS 9 applications must be installed on a Mac OS Extended format disk to use them with the Classic environment.
    To install Mac OS X on the same disk or disk partition as Mac OS 9, the disk must be in Mac OS Extended format. If it isn’t, quit the Installer and back up your files, then reformat the disk.
    You can also partition your hard disk into several volumes before you install Mac OS X. In the Installer, choose Utilities > Open Disk Utility and click Partition. Partitioning the disk erases the entire disk, so be sure to back up your files first.
    Installing optional software
    Easy Install installs all the software you need to use Mac OS X, but does not install some additional software. If you want to install this optional software or you don’t want to install all the software installed using Easy Install, click Custom Install and select the items you want to install. If you want to install this optional software later, insert the Mac OS X Install DVD and double-click Optional Installs.
    Locating the Installer log
    When you install Mac OS X, the Installer saves a log of the installation. To see the log, open Console (in /Applications/Utilities), click Logs, then click the triangle next to / var/log and select install.log.
    Reinstalling Mac OS X
    To reinstall Mac OS X, insert the Mac OS X Install DVD and double-click the Install Mac OS X icon, then follow the onscreen instructions. When you see the “Select a Destination” pane, click Options to select how to install Mac OS X:
    • Select “Archive and Install” to save your existing system files, user accounts and their home folders, and existing network settings. The Installer saves files in a folder named Previous System so that you can copy them to an appropriate location later. You cannot start up your computer using the Previous System folder.
    • Select “Erase and Install” to erase the destination volume and install a new copy of Mac OS X. If you select this option, you will lose all your files and the software you have installed on the destination volume, so you may want to back it up first. If you select this option, you can choose the format for the volume. In most cases, choose Mac OS Extended (Journaled) from the pop-up menu.
    Setting up and connecting to the Internet
    If you have an existing Internet service provider (ISP) and you’re installing Mac OS X for the first time, you need to enter your Internet connection information when installation finishes. Be sure to have the information available. If you have problems connecting to the Internet, contact your ISP to make sure you have the correct information.
    Advice about using Mac OS X If you have problems starting up
    If you cannot start up your computer, insert the Mac OS X Install DVD and restart your computer while holding down the C key. Choose, Choose > Open Disk Utility, then click First Aid to repair your disk.
    If you have problems starting up your computer and you have devices connected to your computer such as FireWire drives, USB printers, or external displays, try disconnecting them before starting up again.
    Upgrading your applications and other software
    For best results with Mac OS X, look for versions of your applications that are built for Mac OS X. Check the Mac OS X website for information about available applications:
    • www.apple.com/macosx/
    If you cannot find Mac OS X versions, upgrade to the latest Mac OS 9 version to use with the Mac OS X Classic environment. Check with the manufacturers for the latest updates.
    Using POP email accounts and On My Mac mailboxes in Tiger and Panther
    If you have a shared home folder and you access a POP email account using Mail in both Mac OS X Panther and Mac OS X Tiger, you will not see messages that you retrieve in one version when you switch to the other.
    As an alternative, you can deselect the option to remove copies from the server after retrieving your messages. To change this option, open the Accounts pane of Mail preferences and click Advanced.
    You will not see messages saved in a mailbox on your computer when you switch from one version to another. To avoid this problem, use separate home folders for each version of Mac OS X.
    Your IMAP account will synchronize automatically when you switch between Mail in Tiger and Panther.
    © 2005 Apple Computer, Inc. All rights reserved. Apple, the Apple logo, FireWire, Macintosh, Mac OS, and Power Macintosh are trademarks of Apple Computer, Inc., registered in the U.S. and other countries. PowerPC is a trademark of International Business Corporation, used under license therefrom.

  • Problems Restoring Erasing Drive: Cannot Unmount Disk

    I just intalled an SSD in my macbook pro, and would like to use my old hard drive as a storage disk. When i boot into the ssd (mountian lion) and try to erase the old disk it says it cannot unmount the disk. i have also tried booting off an external disk (also mountain lion) and i get the same problem. Any ideas would be greatly apprectiated.

    Sometimes when DU can't unmount a drive or volume it's because something else like Spotlight or TimeMachne has it in use. Set your Spotlight to ignore the drive.
    Also try using command r booting into Recovery for Disk Utlity there, it doesn't have Spotlight, TM or anything like that so it should unmount the drive.
    If your still having problems and you don't care about the data on the drive, then you can try buring a disk of Parted Magic ISO and see if you can option key or c key boot off of it and go hog wild messing up the drive's data and boot flags.
    Once that's done use Recvoery to Secure Erase (middle selection) and that will take care of it, then format GUID OS X extended journaled, GUID or MBR + exFAT or whatever.

  • Cannot unmount disks

    Hi:
    I have been reading the post here in the Mac Pro forum for about six months and this is my first answer (and my first problem with my MP)
    In short, the problem I am having is that Carbon Copy Cloner, wich I have been using for cloning my start up disk to a second internal HD without any problem since I bought my MP, has stopped doing so. The message “can not unmount disk“ shows up. Can not unmount in Disk Utility neither. So, I can not clone my disk as my normal security routine. Rebuilding start up disk´s directory (wich I do before every week clone) with DW4 is not longer possible, nor even booting from DW4 cd. This started happennig after my first system freeze and the installation of a 3rd HD in bay 3 (the same day and in that order) After freeze I repaired with Maintenance, then I installed the HD.
    Any help will be very, very wellcome.
    (and excuse for my english, guys.)
    Mac Pro   Mac OS X (10.4.10)  

    Hi The Hatter:
    I do appreciate very much your help in this matter. I have learned a lot reading your answers to another peolpe´s questions.
    To the point:
    MAINTENANCE is a system maintenance and cleaning app. I switched to it from ONYX. Take a look at it at:
    http://www.titanium.free.fr/pgs2/english/maintenance.html
    I am sure you know well this app, but maybe I wrote its name in a funny way. I do my cleaning tasks with MAIN MENU as well. Wich one is the best, in your opinion?
    I do boot from my clone disk every week. From it I repair the directory of my “main“ disk. Then I restart and boot from my “main“ disk and clone it (using CCC) to my Back Up HD. I do reuild the directoy before cloning following a recommendation I found in Bombich´s forums. This is about not to cloning a already “deffective“ system. When this problem appeared I booted from DW cd as a last option procedure.
    You are right!!! I would be doing better with a Emergency Partition. I have been lazy on this point.
    Until now, I thought that running maintenance scripts and cleaning with MAINTENANCE (or ONYX) and rebuilding directory before cloning to another HD would keep me safe.
    Know I believe that to be safe the best I can do is not to have a computer and move to a deep, fresh and green forest.
    So. Wich is your maintenance and back up procedure, Hatter? I am stilI learning and am sure that it would be a good thing to know how do you keep your machine safe.
    (But think about the forest, Hatter... Think about it...)
    Mac Pro   Mac OS X (10.4.10)  

  • Cannot unmount disk from standard user account (bound to AD)

    I have an intel iMac running 10.8.2 with problems unmounting disks. This isn't an issue from administrative accounts. However, any standard account requires authentication by an administrator to unmount a disk. I ran top while trying to unmount the disk and noticed that the daemon securityagent kept emerging. Unfortunately I can seem to modify any config or plist files to stop this prompt from happening. I need standard users to be able to mount and unmount disks from the machine. Here is what I've tried:
    Safe booting
    removing the plugin at /System/Library/CoreServices/SecurityAgentPlugins/DiskUnlock.bundle
    Writing an Applescript running a diskutil command with administrator privileges (I'm sure the syntax was fine because it worked on a 10.7 machine)
    removing com.apple.unmountassistant.useragent.plist
    Disk Utility
    I might be forgetting a step or two but that's about it. Any ideas?

    Open Console in Utilities & see if there are any clues or repeating messages when this happens.
    Could Spotlight or TM be running on those drives in that account?

  • Cant Partition Disk- "Error Cant unmount Disk"

    Im trying to partition  my Macintosh HD and install FCP X on the new partition, because I want to still use my Final Cut Studio when needed. I want to install MAC OS on the new partition so I can use it as a start up disk as well. I followed the instructions as directed.
    I restarted my computer and held the command and "R" key. In the disk utility I selected my HD and selected 2 partitions. I named them and entered the size and selected GUID as scheme. but when i hit apply i get " Failed, cant unmount disk" can someone tell me how I can successfully partition my HD.

    You can't unmount the boot volume, which contains the virtual Recovery HD. Try again, launch DU, select the disk, select Partition, and click on the + sign at the bottom.

  • Failure erasing and restore partition on PB, "cannot unmount disk"

    Hi,
    I would like to erase a partition that I have on my 30gb internal harddrive.
    I get an error message saying something like "cant eject/unmount the disk" same error message when I run the diskrepair.
    when I did the restore thing ( disk image of installdisk OSX 10.4) (I skipped the erasing and whent straight for restore) I got another error message. (saying something something and (-10000))
    What can I do to erase the partition and restore

    Calle:
    I would like to erase a partition that I have on my 30gb internal harddrive.
    Do you have more than one partition on the HDD? I suspect you have only one since the HDD is only 30 GB.
    Your computer is now 8 years old, as is the original HDD. The average life of these drives is 3 to 5 years, so your HDD is well past old age. You may be getting the error messages because your drive is failing.
    cornelius

  • Cannot unmount disk - Mac Mini

    Hello! I recently purchased a used Mac Mini (specs provided below) from a friend, and I am starting the process of erasing all of his old data. The Mac Mini has two hard drives, MAC HD1 and MAC HD2. Only one of the hard drives was being used, MAC HD1, and had OS X Yosemite installed on it. I did some research and found out that to erase the first hard drive I needed to create a bootable USB, which I did using DiskMaker X and a 64 GB thumb drive (only one I had over 5 GB). That process was successful, and I then restarted and pressed ALT on my windows keyboard upon startup. I selected to boot using my thumb drive, and that seemed to work fine as well. I then selected Disk Utility and chose MAC HD1 from the choices on the left side. However, when I try to erase, I get an error that says "Volume Erase Failed with this error: Couldn't unmount the disk." Then when I try to unmount from the menu above I get "The disk
    MAC HD1 could not be unmounted. Make sure that all applications and files are closed on the disk." I am a pretty tech-savvy guy, and my friend and I proceeded to put about 4-6 hours into trying to find what application/program/process might be keeping the disk from unmounting. We tried using sudo commands in terminal to kill spotlight, deleted every application/file that we could, and force quit everything and relaunched Finder. No luck. We decided to download What's Keeping Me, a program that shows processes and applications that are using the disk itself. Weirdly, it didn't show any processes for MAC HD1, but we looked closer and through a options window opened all open files on MAC HD1, which seemed to be at least 300. However, the list was just text, and we were unable to find out how to close any of them. I tried going to the Apple Store and they didn't help either. I'm simply wondering what it would take to unmount my MAC HD1 disk so I can finally get to using my purchased Mac Mini.
    Side Note:
    If this changes anything, my friend did say he was using the Mac Mini for a server of some sort, but he thought he turned it off already.... Anyways, just giving extra knowledge I know about the problem.
    Specs:
    Model Name: Mac mini
    Model Identifier: Macmini4,1
    Processor Name: Intel Core 2 Duo
    Processor Speed: 2.66 GHz
    Number of Processors: 1
    Total Number of Cores: 2
    L2 Cache: 3 MB
    Memory: 8 GB
    Bus Speed: 1.07 GHz
    Boot ROM Version: MM41.0042.B03
    SMC Version (system): 1.65f2
    - Landon

    the Lion Installer ( OSINSTALL.MPKG ) does more then only check for the CPU.
    1) It checks CPU for 64bit capable ( core2duo and all later )
    2) It checks for the presence of minimum 2*1024 ( 2048MB Ram )
    3) It checks the SerialNumber, Board ID, MacModel Name, Year of Production and SMBios Version if they are whitlisted as "ok to install". The Installers "Distribution" file contains also MacModel IDs  that are blocked completely.
    Obviously your Mac Mini does not pass check 3) as your Mini is one of the blocked ones.

  • ERROR: CANNOT UNMOUNT DISC.  help!!

    i am returning a leased computer and need to erase everything. I used disc utility with firewire to my G5. everything is ok till i get this message??. what's up?

    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'.

  • Couldn't unmount disk

    OK so here's the deal, I had windows 8 installed using boot camp, Then when I went to uninstall it using boot camp, it gave me an error message, when I closed everything, I opened boot camp and the remove windows 7 option was no longer there, it was install windows 7, so I opened disk utillty and there wasn't a boot camp drive, however, when I went to partitions, boot camp wasn't there but macintosh HD didnt take up all the space and there was a grey area beneath the Macintosh HD, I dragged the Macintosh HD to the bottom and clicked apply, I got an error meassage which I solved by repairing the disk. So when I try it again, the process progresses more and then I get another error message that says couldn't unmount disk. All of this done from the Recovery partition. What Im going to do now is put mountain on an external hard drive and boot from that and try again. Guys please HELP AND REPLY PLEASE!!!!!!!!
    This is the grey area I was talking about, I tried repairing macintosh HD but I still get the same message

    I had a similar problem as the thread starter, and was able to fix it by making a bootable Mountain Lion Recovery Volume on a USB stick, as Courcoul suggested above (http://support.apple.com/kb/DL1433).
    I had removed bootcamp and the associated partition from my Macbook Pro running Mountain Lion, and I wanted to reallocate that space on the hard drive to my main Mac partition.
    The bootcamp assistant had failed halfway through the process, and it could not extend the partition to include the unallocated space ("partition failed"). It had also created errors on my main Mac volume (when scanning with Disk Utility).
    1) The Disk Utility inside Mac OS was not able to repair the volume, so I had to boot from the recovery partition (cmd + r during boot), and then repair them. This would let the errors be repaired, but still I would get the error "Disk Erase failed with the error: couldn't unmount disk" when I was trying to resize the partition to include the unallocated space.
    2) So Finally, when booting from the recovery USB stick, and using Disk Utility, I was able to resize the main partition to the full size of the hard drive.
    I think the error "couldnt unmount disk" was due to the fact that somewhere in the process it said it was trying to "relocate the recovery partition". So I assume that if you boot from this recovery partition on the drive, it cannot do this part, and the process fails.
    Thank you all very much! Your comments were really helpful. I hope my explanation is useful to someone with the same problem. 

  • Disk utility can't unmount disk

    Hey there,
    A few days ago, my mac began to start up incorrectly; with a black screen right from the beginning.
    I ran the disk repair with the disk utility program and it told me, that my hard drive couldn't be repaired. So I booted the mac in recovery mode and tried to erase the hard drive. After a while, an error appeared, telling me "cannot unmount disk".
    I tried to "force unmount" via terminal, but that didn't work as well.
    Does anyone has any tips for me, before I'm going to the apple support.
    Thx in advance.

    It sounds like the hard drive is failing. The only real advice here is to make sure you have a good backup. If it's under Applecare, Apple will replace the drive but you'll probably lose your data. The other thing you can do is replace it yourself if you're outside Applecare. Look up the specific procedure for your model at ifixit.com.

  • How to unmount disk w/ OS X 10.7 Lion

    I have a used 2007 Mac Pro 2,1 Tower. It came w/ Lion 10.7 already installed, licensed to the previous owner (or maybe even someone else! bc he does not know the password for the Mac, which is where my trouble began - couldn't make any changes to the comp). I ordered 10.6 Snow Leopard from Apple that I may begin a fresh install and get my own AppleID for upgrades, purchses from app store, etc.
    Here's my problem:
    I tried to erase using "zero out data" and received this message: "Secure Disk Erase failed - Secure Disk Erase failed with the error: Couldn't unmount disk".
    I have read that the reason you cannot unmount disk is because you booted on the RecoveryHD where the OS X is installed. Any one have a work-around for this? I need to erase the entire HD to start over. No back-ups needed as I haven't done anything on the comp. Thanks.

    You need to boot the system from the Mac OS X 10.6 installer disk and run Disk Utility from the menu there. Then you can repartition and erase the disk.
    Regards.

  • Disk Util cannot unmount ext HD to format or partition

    Computer:  MacBook Pro Retina 13" latest model.  All updates have been applied.
    I have a 1TB WD external harddrive.  It has 2 partitions (1 FAT32, 1 Mac OS Extended).  This drive was working properly until one day it stopped mounting.
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    - FAT32:  Mounts in OSX but will not unmount.  I can access FAT32 partition via Parallels (Win7).
    Bigger Problem:  I'm cannot re-format or re-partition the drive.  Disk Utility provides an error that the drive cannot unmount.
    Any help is greatly appreciated.

    I made a mistake in the original post.  I CANNOT access the FAT32 via Parallels because it will not unmount from OSX.
    This is how I fixed it....
    Booted up my Windows laptop and used Computer Management to delete both volumes (partitions). 
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    Booted up MacBook and used Disk Utility to re-format as Mac OS Extended.
    This appears to work fine, and I am able to use it for Time Machine now.
    My question now is:  How could I have accomplished this in OSX?  I know some people will say maybe the drive is going bad.  For this question, let's assume it's ok. 

  • Boot Camp error: The startup disk cannot be partitioned or restored to a single partition. The startup disk must be formatted as a single Mac OS Extended (Jounraled) volume or already partitioned by Boot Camp Assistant for installing Windows.

    Hi!
    I am getting the error:
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    I read up some on google, but all of them says that they have crated a partition and that is the problem, I only have the standard "Macintosh HD".
    I tried to create a partition manually in disk utility but then the error message: "Partition failed with error message: Could not unmount disk."
    Can anyone help me? It's driving me crazy.
    Thanks.

    This message, and threads like yours got asked daily for over two years, now it is only a couple times a week!!
    Is it so hard to follow through? you were to have backup already, clones are best, then erase/format and restore.
    Then partition.
    Some have been able to use Disk Utility booted from OS X DVD or another drive, and repair the drive.
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  • Help needed with delete of bootcamp partition, error message 'Couldn't unmount disk'

    Hello all
    Sorry if this issue has been repeated elsewhere, I did search but there wasn't a discussion relating to my specific issue.
    When we bought the iMac a couple of years ago, my husband partitioned the hard drive to run Windows via Bootcamp. Having got used to the Mac and experiencing the frustration between having to reboot to access each partition I have decided to restore the Mac to factory settings and install Parallels 8 so I can continue to use Office and Coreldraw).
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    I then selected the main drive and the tab 'Partition', from the layout I then selected Bootcamp and clicked the minus button. I get the message confirming which partition I am about to delete and hit remove. I then get the error message 'Partition failed: couldn't unmount disk'.
    I would be very grateful for some help please? I am not the best techy person but happy to give anything a go.
    Just to mention there is nothing left on the Mac that I want to keep, therefore if there is an easier way than having to delete the partition then happy to hear it.
    Thanks
    Tara

    Hello Tara,
    Are you using Filevault?
    https://kimmo.suominen.com/blog/2013/03/file-vault-volumes-cannot-be-resized/
    Also see the last few posts here...
    https://discussions.apple.com/thread/3894449?start=15&tstart=0

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