osx - Starting Windows 7 from an external hard drive on a Mac

07
2014-07
  • Richie2154

    I would like to run windows on my MacBook Air with Mavericks 10.9.3. I currently have a Windows 7 64 bit ISO I can use. The problem is that my MacBook does not have enough space to install windows and be able to install the things I need. I have an external hard drive with 750 GB of space and if needed an external CD drive.

    • Answers
  • Martin

    Sure, Why not

    Even though Mavericks has it's own set of issues compared to previous versions

    You can Run Windows 7 in OS Mavericks

    Just Make sure you have the External Hard drive Connected

    Run the Installation of Windows 7 and tell it to install it on the 750GB Hard Drive

    it should go smoothly from there

    You just need to remember that when you want to boot into windows, You need to have that Hard Drive Connected

    Your other option is a Virtual Machine within Mavericks that Installs Windows and Accesses it from that External Drive

    Hope that Helps Let me know if you need further help

  • Wes Sayeed

    Short answer:

    No. While the Mac has no trouble at all booting off just about anything that can be plugged into it, the issue is what Windows 7 supports, and Windows 7 does not support booting from external media.

    Long answer:

    Yes you can, but it's a total hack, only works with Thunderbolt drives (not USB drives), and is not supported by either Microsoft or Apple.

    It must be done in EFI mode. Here's a link to instructions: Is it possible to install and boot Windows on a Thunderbolt drive?

    On a side note, it IS possible to boot Windows 8 from USB drives, but it too is not supported by Microsoft unless you have the Enterprise edition and a USB 3.0 flash drive from a very short list of supported flash drives


    • Related Question

    installation - How to setup Windows from an external hard drive?
  • Amr ElGarhy

    Is it possible to install Windows from an external hard drive?

    I have Windows XP installed on my laptop, and I want to remove it and install Windows 7.

    My Windows 7 installation is in an .iso format on an external USB hard drive.

    Is it possible to install it or will I need to put in a DVD before I start installing?


    • Related Answers
  • slhck

    Follow the directions here:

    1. Plug-in your USB flash drive to USB port and move all the contents from USB drive to a safe location on your system.

    2. Open a Command Prompt with admin rights. Type "cmd" into the Start menu search box and hit CtrlShiftEnter.

    3. Type DISKPART and hit Enter … Next type LIST DISK and note down the Disk number (e.g. "Disk 1") of your USB flash drive.

    4. Next type all the below commands one by one.

      SELECT DISK 1
CLEAN
CREATE PARTITION PRIMARY
SELECT PARTITION 1
ACTIVE
FORMAT FS=NTFS
(Format process may take few seconds)
ASSIGN
EXIT

      Don’t close the command prompt as we need to execute one more command at the next step. Just minimize it.

    5. Next insert your Windows7/Vista DVD into the optical drive and check the drive letter of the DVD drive. In this guide I will assume that your DVD drive letter is “D” and USB drive letter is “H” (open my computer to know about it).

    6. Maximize the minimized Command Prompt in the 4th step.Type the following command now: D: CD BOOT and hit enter.Where “D” is your DVD drive letter. CD BOOT and hit enter to see the below message.

    7. Type another command given below to update the USB drive with BOOTMGR compatible code.

      BOOTSECT.EXE /NT60 H:

    Where “H” is your USB drive letter. Once you enter the above command you will see the below message.

    1. Copy your Windows 7/Vista DVD contents to the USB flash drive.

    2. Your USB drive is ready to boot and install Windows 7/Vista. Only thing you need to change the boot priority at the BIOS to USB from the HDD or CD ROM drive. I won’t explain it as it’s just the matter the changing the boot priority or enabling the USB boot option in the BIOS.

  • Cory

    You can use an external USB hard drive or flash drive. The steps to install from a USB hard drive can be found here:

    Use a USB hard drive to make a bootable Windows 7 install

  • dreamlax

    The BIOS needs to support booting from a USB storage device, and the device needs to have a boot sector. If there is no boot sector then you cannot boot from the device. Unless the boot sector contains or loads code that is capable of reading a bootable ISO image, then no, you cannot boot an ISO image on an external storage device.