Fixing "Setup was Unable to Create a New System Partition" Error While Installing Windows 7 via Bootcamp

Kelly Heffner Wilkerson

Categories: macOS | View Comments

This is a little bit outside the scope of this blog, but I can't help myself. I recently got a new iMac, and tried to install Windows 7 on it using Bootcamp -- this is usually a painless process, but with the removal of DVD drives on the iMac and USB 3, it's a world of hurt. Here's my rundown of what worked seamlessly for me, after repeated bouts of getting stuck at the error "Setup was Unable to Create a New System Partition" during the Windows 7 install1.

  • If you have any half-completed installs, use the Bootcamp Assistant to remove the broken windows partition (in Bootcamp packaged with Mavericks, that should be checking the last checkbox only, to "remove").

  • Forget about installing form a USB thumb drive, and use an external DVD drive with a Windows 7 install disk2. (Use the Disk Utility to burn the ISO to the DVD if needed. You can download the ISO file for Windows 7 Ultimate, which will allow you to install Home, Ultimate, etc flavors of 64-bit Windows 7, here.)

  • Plug in your USB thumb drive, which we will still use to hold the Apple support files.

  • The ordering of things plugged into the USB ports seems to matter. On my iMac, there are four usb ports at the back; facing the back of the iMac from right to left I had: external DVD drive, thumb drive, blank, apple keyboard w/ non-apple mouse plugged into keyboard.

  • Use Bootcamp Assistant:

    • Uncheck the option to copy the installation files to a USB thumb drive. We don't need to copy the iso to the thumb drive, since we're using DVD.

    • Check the option to copy the support files to the thumb drive. We need these for Apple hardware drivers.

    • Check the option to install windows. We desperately want to do that!

  • If you've been trying to install from a USB thumb drive, you'll probably get a message about making the thumb not bootable. That is correct: we want to make the USB thumb drive not bootable now, as we are booting from the DVD and just using the thumb for support files.

  • Now the installation should work. Select the bootcamp partition, choose advanced, choose to format the BOOTCAMP partition as usual. Remember which partition said BOOTCAMP before you partition :)

  • Dance around your office (optional, but recommended!)

I believe the root of this issue is a unhappy melding of USB 3.0 issues and having a bootable USB thumb drive be the source of installation.

Edit: Since the writing of this article, readers have sent me feedback that using USB 2.0 thumb drive works. That is great news (especially since a USB DVD drive isn't always lying around anymore) and I appreciate the feedback from people sharing their experiences!

  1. I've also summarized in the Apple forums here! 

  2. The external DVD drive I used was an Apple USB SuperDrive. I borrowed it from a friend! 



MICHAEL MOORE November 11, 2014



Mark October 10, 2014

Excellent advice! This worked for me. Thank you.

Kelly HW

Kelly HW October 10, 2014

Yay! Thank you for commenting too!

Did you use a DVD drive or a USB 2.0 thumb drive?


Mark October 10, 2014

DVD drive. Only downside is that I was too cautious on my bootcamp partition size. I'm going to have to do it again now with a bigger partition :(

Kelly HW

Kelly HW October 10, 2014

I've also been told now that an 8GB USB 2.0 thumb drive should work also, so dig around in your desk drawers for some older drives!