How do I create a bootable USB with Windows 7 SP1 64bit using OS X?

I need to setup a fresh new ASUS laptop, the only thing I have is – Macbook Pro.

What I have:

  1. Fresh new ASUS laptop with FreeDOS,
  2. An ISO image of Windows 7 SP1 64bit,
  3. An 8Gb USB flash drive,
  4. A MacBook Pro running OS X 10.9.5.

What I know so far:

  1. Creating a bootable USB drive using BootCamp is not working for me. After inserting the stick to ASUS laptop, it simply won't start the Windows setup process.
  2. There's a "UEFI" next to USB bootable option in ASUS's BIOS. This suggests I need to somehow create a UEFI-compatible bootable USB. In turn, "UEFI-compatibility" means checking 3 things which I have double-checked.

I am familiar with Terminal (being a web developer myself), so any command line tricks would be more than appreciated.

P.S. Googling isn't helping much, which is strange. This suggests I'm not googling the right keywords...

  • If you're talking actually running Windows from the USB drive, Windows 10 allows this via a feature called "Windows To Go". For Windows 7, you're definitely in "unsupported and not allowed by license" territory. If you're talking just the installer, things are much simpler. Jan 27, 2019 at 1:03

2 Answers 2


First of all, I'm not a Mac user, so I'm doing this purely from a Unix perspective. First of all, you need to convert the ISO file to a disk writable IMG file.

hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/windows.iso

Then we need to unmount the USB-stick to write an image to it. To do this we need to know the device address, which can be found by running diskutil list, plug the USB stick in, then run diskutil list again to determine the device. After this, run

diskutil unmountDisk /dev/<theusbstick>

Now we are going to use the dd command to write the .img file to your USB stick.

sudo dd if=/path/to/target.img of=/dev/<theusbstick> bs=1m

Now to safely remove the USB stick to prevent data corruption, run

diskutil eject /dev/<theusbstick>

Good luck!

Source: http://www.ubuntu.com/download/desktop/create-a-usb-stick-on-mac-osx

  • Thank you Thandruil. Since your instruction is not explicitly stating this will work with UEFI, I believe you tried it and it indeed works? Can you confirm that? Feb 26, 2015 at 19:57
  • UEFI or Legacy means the way you boot this device, further than that it has nothing to do with how you write to your USB stick in this case. If you choose to boot the USB stick with (U)EFI, it will boot as UEFI. To confirm, I've used this method (but on Debian Linux) to make my own install stick for Windows, which is installed with UEFI now.
    – erikgaal
    Feb 26, 2015 at 20:09
  • Thank you, Thandruil. I didn't find a way in BIOS to select how to boot the USB, unfortunately. It always shows a "UEFI" next to the bootable device, that's it. I will try your method now. Feb 26, 2015 at 20:15
  • That should be no problem, if you really insist on booting as Legacy, you need to change your boot option to only boot as Legacy (BIOS).
    – erikgaal
    Feb 26, 2015 at 20:16
  • By the way, why converting ISO to IMG? Feb 26, 2015 at 20:25

Found a workaround. Installed Windows using a DVD I burned ISO into (first time in no less than 5 years!).

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