Windows 7: Setup was unable to create a system partition or locate an existing partition.

Over the past week, I’ve installed Windows 7 and OS X more times than I can count. In attempting to figure out the easiest way to dual boot Windows 7 and OS X, I’ve also partitioned my drive a good 30+ times. So.. after messing up with an EFI bootloader, I was suddenly unable to re-install Windows 7. I encountered the error: Setup was unable to create a system partition or locate an existing partition. I also ran into the error: Windows cannot be installed on disk 0 partition 1.

I used Gparted to repartition my drive, and even used Disk Utility but repeatedly encountered the above errors.

As it turns out, I had another System disk attached (OS X on a USB drive) to my laptop and once I unplugged it, I was able to successfully install Windows 7.

Chrissy is a PowerShell MVP who has worked in IT for nearly 20 years, and currently serves as a Sr. Database Engineer in Belgium. Always an avid scripter, she attended the Monad session at Microsoft’s Professional Developers Conference in Los Angeles back in 2005 and has worked and played with PowerShell ever since. Chrissy is currently pursuing an MS in Systems Engineering at Regis University and helps maintain RealCajunRecipes.com in her spare time. She holds a number of certifications, including those relating to SQL Server, SuSE Linux, SharePoint and network security. She recently became co-lead of the SQL PASS PowerShell Virtual Chapter. You can follow her on Twitter at @cl.

Posted in Windows
3 comments on “Windows 7: Setup was unable to create a system partition or locate an existing partition.
  1. Nice! Only a real nerd would have OS X mounted on a USB drive! Only a classy nerd would admit this partitioning blunder on the Internet!

  2. Eric J says:

    Yeah, same thing happening to me right now. Except the usb drive is for my raid drivers. The same thing happened when I was installing vista, but I just can't remember for the life of me how I fixed it. I just know it was something extremely simple that I overlooked time again.

  3. tankman says:

    I can shed some light on the "Windows cannot be installed on disk 0 partition 1." I came across this on 4 different drives, the first 2 had Gparted run on them just a few minutes before. I thought this was the problem but it isn't.

    Here is what I found. Even though you can swap drives (SATA) during the install process, you can not use the new drive unless it was there during the system post during boot as the BIOS has to see the drive for some reason (I never had this problem in Linux).

    So, the next time you have this error, turn the machine off, make sure the target HD is plugged in and start it up. If the BIOS doesn't see the drive you will get this error.

    I was about to give up on this as it just didn't make sense. Very frustrating!

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