Virtualbox – 1 differencing child hard disks

Posted on November 7, 2009 by Matt

If you’re getting an error along the lines of “{hard disk} cannot be directly attached to the virtual machine because it has 1 differencing child hard disks”

Then the solution is to delete the virtual machine (but not the hard disk!) and then recreate the machine using the hard disk.

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  • Peter Blok

    Thank you. Saved my day!

  • Peter Blok

    Thank you. Saved my day!

  • em

    Note: You can clone a snapshot, to create a new disk with this command:

    VBoxManage.exe clonehd xxxxxxx-xxxxx-xxxxxxxxxxxxxx tempnew_drive_image.vdi

    xxxxx… is the snapshots UUID (identifier in the snapshotdirectory)
    It takes a while to process however.

  • Skumara2000

    Thanks you.

  • Gregorslaw

    Thank you. I was so desperate that yesterdays whole work was gone. Hate to use windows but sometimes there is no way around. For me at least until wine works good with Indesign.

  • Marko

    I get this error when i decided to took a snapshot, but terminated the operation.
    I dealt with the problem when created a new VM from the old virtual hard disk.

  • Danny

    Thanks for the tip! I tought that could start all over again, but everything is working again! :)

  • Guest

    thanks ,got my VM back ! ,this happened when i cancelled a snap shot.

  • Seb Smith

    SPLENDID! I’ve spent HOURS messing around with instructions from other sites regarding cloneing virtual machines and messing around with the XML and your simple solution worked A1! :) THANKS!

  • Anonymous

    Thanks Matt! I started to have install-windows nightmares as this message popped up. But there you were with an unbelievable simple and effective solution.

  • Vboxer

    u da man matt!!! saved the day! thanks much!

  • Neo Mhacker

    Oh my God. I am new to working with VMs. I thought all the work I had done in that system is lost. I was going to redo some three days of work. Thanks to you :) One of the smallest yet effective technical posts I have ever read.

  • http://www.schubladenschaf.de/virtualbox-hard-disk-cannot-be-attached/708/ VirtualBox: Hard disk cannot be attached

    [...] bei That Matt beschrieben, gibt es eventuell eine einfache Lösung: Löscht die bisherige Virtuelle Maschine [...]

  • El

    Thank you so much, honestly, this was the most simple yet effective solution.

  • http://twitter.com/mackel_eu Marc Hecht

    Thank you em. This solution works perfectly.

    So more detailed:

    You go to “C:Users{Your Username}.VirtualBoxMachines{Your Machine Name}Snapshots”
    and you will see a file like this: “{10c4f98c-5480-470d-9a9a-b8b63b4d3a96}.vdi”
    This ist the patial harddrive that is merged by VBox for this snapshot.

    So this VDI can not run alone. You have to merge it, before creating your new “Backup-Machine” as em stated before, do that with this command:

    VBoxManage.exe clonehd xxxxxxx-xxxxx-xxxxxxxxxxxxxx tempnew_drive_image.vdi

    You must replace the XXXes with the UUID in the filename you saw before. On my case it was: “10c4f98c-5480-470d-9a9a-b8b63b4d3a96″ so i had to use this command like this:

    VBoxManage.exe clonehd 10c4f98c-5480-470d-9a9a-b8b63b4d3a96 D:XP-New.vdi

    So now create a new machine and select the new Harddrive-File as harddrive (in my case: “D:XP-New.vdi”) and run the new Machine.

    It take about 8 minutes to resore my last used state of virtual harddrive.

  • Pepeluis

    thanks, very usefull, gracias muy util

  • Ching Ling

    I have a few detailed steps to contribute :

    1.Load the VirtualBox Manager2.Click “New”3.fill out all the basic info4.On the “Virtual Hard Disk” tab select “use existing hard disk”5.Browse for your existing hard disk6.Select your .vdi file and click continue7.Finish the remaining steps and start up your new Virtual Machine

    i copied this from this site :

    http://itslennysfault.com/virtualbox-error-has-1-differencing-child-hard-disks

    thanks.

  • Juan

    Realmente Funciona, Gracias
    León, Guanajuato; México

  • Mark Stimson

    This post has jost dug me out of a huge hole that was driving me nuts today – many, many thanks

  • Ron

    worked perfectly. many many thanks

  • http://twitter.com/timhibbard Tim Hibbard

    Thank you!

  • Em

    That’s exactly the scenario I had.  I had a snapshot that was taking too long, so I terminated the operation, but I had done a couple of other things so hadn’t tied the cause and effect together.  Thanks for helping me figure out why.

  • Mazhar

    Thanks a million, you saved me 10 days of efforts.