MBA - what are disk 2 and disk 3 ?

Discussion in 'MacBook Air' started by The Mercurian, Feb 15, 2014.

  1. The Mercurian macrumors 68000

    Mar 17, 2012
    I'm selling a 2013 MBA and so am reinstalling OsX.

    In Disk Utility there are a disk 2 and a disk3 showing up. Both are about 5GB.

    Whats this about ? Is it normal ?
  2. DmbShn41, Feb 16, 2014
    Last edited: Feb 16, 2014

    DmbShn41 macrumors 6502

    Jun 22, 2009
    One of the disks will be the recovery partition. This is an automatic function of OS X and is non user removable. If you reboot computer, and hold Option down while booting, you'll see all bootable partitions available to the computer(external bootable drives also if one is plugged in). One should be your Hard Drive, and the other the Recovery partition. If you're seeing a disk 3 that could mean that you have a Boot Camp partition for Windows?

    Reboot and hold Option down and tell us what you see.
  3. scaredpoet macrumors 604


    Apr 6, 2007
    Are you using FileVault on your MacBook Air? If so, that would explain the second of the three volumes. The system needs an unencrypted basic boot volume to let the Mac know what to do upon boot up, like bring up the login screen, accept a password and mount the FileVault drive.
  4. alphaod macrumors Core


    Feb 9, 2008
    See if you can mount them and see what they contain.

    FileVault does not need these volumes. Only BitLocker needs these.
  5. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    No it is not normal.

    The Recovery HD partition would by 650MB and its not normally visible in DU unless you enabled developer mode.

    Do you have any external disks attached?

    If not, it looks like you installed something that modified the default partition layout. Even Filevault2 does not look like this.

    To get rid of it do a command-option-r boot to Internet recovery. When the recovery screen comes up start Disk Utility then select the drive itself at the top (like Apple 120GB or whatever... this is above all the partitions) and go to the erase tab and erase the entire disk to Mac OS Extended (Journaled). Then quit Disk Util and click reinstall OS. This will get you back to the default single partition with a clean install of the OS version that came from the factory.
  6. The Mercurian thread starter macrumors 68000

    Mar 17, 2012
    Thanks all,

    As weseal boy suspected i had an external drive connected. I was a bit slow ont he day but i eventually realised one disk was the USB I had booted off :rolleyes: and the other was the recovery partition. Mystery solved!

    Thanks anyhow for the replies!

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