Installing Windows 7 from USB flash drive on Late 2008 MacBook Air with OS X Mavericks using Bootcamp

Recently I had the opportunity to use a Mac for the first time in my life. If was the second generation of MacBook Air (Late 2008 version) running OS X Mavericks. Because Windows is my usual operating system I decided to install Windows 7 on the Mac using Bootcamp to have the option to use either system.

The problem is that MacBook Air (MBA) doesn't have any DVD drive so you have to install Windows from a USB flash drive. The Bootcamp Assistant on my particular model doesn't support installing Windows from USB, it requires a DVD drive. It gives a warning (see the picture below) and isn't able to find the Windows installation files on the USB flash drive. You get the message "The installer disc could not be found".

On some versions of OS X or perhaps with different version of MacBook Air there is the option "Create a Windows 7 install disk" but that didn't show up on my MBA/OS X.

     Bootcamp warning

 

There are different solutions that can be found on the internet. From modifying Bootcamp configuration files and forcing it to display hidden options or installing rEFIt to trying to install from a virtual machine. None of the methods seemed simple enough to me but I felt that there must be another way. And then I remembered that there exist applications that can create a virtual DVD drive on Windows, tricking the OS into thinking that there is an actual DVD drive connected to or built in the computer. So I thought, what if similar solution exists for Mac? And the answer is yes. I found out that Daemon Tools has a Mac version!

The obvious - mounting the disc image with OS X’s tools - won’t work because the Bootcamp Assistant knows that you don’t have a physical disc in place.

So here is the step-by-step guide how to install Win 7 on your MBA without external DVD drive using USB and Bootcamp. I have only tested this solution on OS X Mavericks (10.9.3) and the late 2008 MBA, but since the software (namely Bootcamp) should be the same I suppose that the same process should work on newer Macs as well.

 

You will need:

1. Bootcamp Assistant (comes with Mac OS X as far as I know but make sure you have the latest version)
2. Daemon Tools for Mac which can be downloaded here. Download the trial version, for our purposes it will suffice
3. Windows ISO image. You can download it legally from Digital River here. Make sure you download the same version that matches your product key!
4. A USB flash drive with at least 4 GB capacity. WARNING: The process will delete all existing data from the USB flash drive. Make sure you back up all your data from it before you begin!

 

The steps:

1. Prepare the bootable USB media. If you have another machine with Windows you can follow this guide that worked perfectly for me.
   If you only have a Mac then some internet threads suggest using Unetbootin to prepare the bootable USB dongle or alternatively you can use this blog post or this one. I haven't tested those for Mac since I was able to prepare my USB on a Windows machine.
   DO NOT INSERT THE USB KEY IN YOUR MAC YET! IF YOU DO SO, BOOTCAMP WILL DETECT THE BOOTABLE USB AND WILL RENDER IT NON-BOOTABLE!
2. Install the Daemon Tools for Mac and use it to mount your Windows ISO image in a new virtual DVD drive.
3. Open Bootcamp Assistant and make sure both options (Download the latest Windows support software from Apple and Install Windows 7) are checked. Then hit the Continue button.
   
   
4. Wait until the Bootcamp finishes and make sure you have your Windows installation USB flash drive at hand because we need to insert it after the machine starts rebooting but before it actually reboots
5. Let the Bootcamp Assistant reboot the machine and plug in the USB flash drive before the grey boot screen appears!
6. Let the Mac boot from your USB flash drive and continue the Windows installation process. (Note: In my case the Windows installer could not for some reason use the partition that Bootcamp prepared for me so I had to delete the partition - the one with the name BOOTCAMP - in Windows installer and create a new one.)

 

Well, that's it. I found it easier than all the other methods out there. Hope it will help you, too.