Creating a Windows 7 USB installation disk on a Mac

Here are the steps to be performed on a Mac to create a Windows 7 USB Bootable Installation Drive.

Steps:

1. Open a Terminal (under Utilities)

2. Run diskutil list and determine the device node assigned to your flash media (e.g., /dev/disk2)

3. Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)

4. Execute sudo dd if=/path/to/downloaded.iso of=/dev/rdiskN bs=1m (replace /path/to/downloaded.iso with the path to where the image file is located; for example, ./windows7.iso)

5. Run diskutil eject /dev/diskN and remove your flash media when the command completes (this can take a few hours on slower drives)

(Note: The sudo dd command executes for around 5 minutes, depends on the USB port and drive.)

If you have access to a different Windows box, try the tool from Microsoft here. There are also manual instructions here. I don't know of any way of making a windows-bootable drive natively in Mac OS X.

I've recently been through this. No matter what I did, I couldn't get my MacBook Pro (can't remember exactly how old it is, but it identifies as "MacBook Pro 3,1") to boot a Windows install disk off anything except the internal SuperDrive, which unfortunately is broken. I tried more things than I can remember, including external DVD drive, USB key, USB hard drive, Firewire hard drive, EFI bootloaders, etc etc etc.

In the end I managed a hack using a trial version of Parallels Desktop - instructions here. If you have a different model Mac to mine, you might find rEFIt helpful - it's an EFI loader that you can run either from your hard drive or a USB key that should hopefully make the experience of booting into the windows install a bit easier...

This is a very old topic but needs some update.

First, Windows 7 is no longer supported by modern Mac. So unless you want to use the installation disk on a PC or old Mac, then Windows 10 is more recommended.

Second, please try to format the USB to FAT32 instead of NTFS or exFAT, which will does not work on Mac. (NTFS is not supported by Mac natively and exFAT won't be recognized as a bootable device in Boot Menu.)

dd command should get the job done for most of cases. However, if you are not a fan of command line, then you can switch to UUByte ISO Editor app (how-to tutorial) or build a Windows virtual machine, which has more free and reliable tools for creating bootable USB from ISO.