joao felipe

Q: Install mac on a fully windows-formatted hard drive (MacBook Air)

I accidentally formatted the whole hard drive on my macbook air to windows. After realising that I did that, I had no choice but to proceed with the windows installation, and now my macbook only has a Windows OS. Is there any way that I can partition the hard drive in windows and format it back to mac journaled so I can install Yosemite back again? After formatting it, what should I do to install Yosemite again?

 

Thank you all in advance.

MacBook Air, Windows 8, Yosemite

Posted on Nov 2, 2014 7:32 PM

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Q: Install mac on a fully windows-formatted hard drive (MacBook Air)

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  • by Kappy,

    Kappy Kappy Nov 2, 2014 7:39 PM in response to joao felipe
    Level 10 (271,328 points)
    Desktops
    Nov 2, 2014 7:39 PM in response to joao felipe

    Only if you partitioned it GUID. Otherwise, you must repartition and reformat the drive in order to install OS X. If you have a 2011 or later model do this:

     

    Install Mavericks, Lion/Mountain Lion Using Internet Recovery

     

    Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.

     

    Boot to the Internet Recovery HD:

     

    Restart the computer and after the chime press and hold down the COMMAND-OPTION- R keys until a globe appears on the screen. Wait patiently - 15-20 minutes - until the Recovery main menu appears.

     

    Partition and Format the hard drive:

     

    1. Select Disk Utility from the main menu and click on the Continue button.
    2. After DU loads select your newly installed hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. 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 Partition button and wait until the process has completed. Quit DU and return to the main menu.

     

    Reinstall Lion/Mountain Lion. Mavericks: Select Reinstall Lion/Mountain Lion, Mavericks and click on the Install button. Be sure to select the correct drive to use if you have more than one.

     

    Note: You will need an active Internet connection. I suggest using Ethernet if possible because it is three times faster than wireless.

     

    This should restore the version of OS X originally pre-installed on the computer.

     

    Otherwise, do this:

     

    Clean Install of Snow Leopard

     

    Be sure to make a backup first because the following procedure will erase

    the drive and everything on it.

     

         1. Boot the computer using the Snow Leopard Installer Disc or the Disc 1 that came

             with your computer.  Insert the disc into the optical drive and restart the computer.

             After the chime press and hold down the  "C" key.  Release the key when you see

             a small spinning gear appear below the dark gray Apple logo.

     

         2. 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.

             After DU loads select the hard drive entry from the left side list (mfgr.'s ID and drive

             size.)  Click on the Partition tab in the DU main window.  Set the number of

             partitions to one (1) from the Partitions drop down menu, click on Options button

             and select GUID, click on OK, then set the format type to MacOS Extended

             (Journaled, if supported), then click on the Apply button.

     

         3. When the formatting has completed quit DU and return to the installer.  Proceed

             with the OS X installation and follow the directions included with the installer.

     

         4. When the installation has completed your computer will Restart into the Setup

             Assistant. Be sure you configure your initial admin account with the exact same

             username and password that you used on your old drive. After you finish Setup

             Assistant will complete the installation after which you will be running a fresh

             install of OS X.  You can now begin the update process by opening Software

             Update and installing all recommended updates to bring your installation current.

     

    Download and install Mac OS X 10.6.8 Update Combo v1.1. You may visit the App Store and re-download Yosemite.

  • by Loner T,

    Loner T Loner T Nov 3, 2014 4:38 AM in response to joao felipe
    Level 7 (24,202 points)
    Safari
    Nov 3, 2014 4:38 AM in response to joao felipe

    If Windows 8 was installed using EFI (which uses GPT partitions), it is possible to shrink Windows and re-install OS X without having to build the Mac from scratch.

     

    Please post the output of the following commands from OS X Terminal (enter your password when prompted).

     

    sudo gpt -vv -r show /dev/disk0

    sudo fdisk /dev/disk0