Greetings All! I am attempting to install Windows 7 on my 2011 iMac running Yosemite. I had just finished a clean install of Yosemite on a freshly installed brand new hard drive. Running Bootcamp, I got the error "The startup disk cannot be partitioned or restored to a single partition". Using the powers of Google, I stumbled upon this article from Apple: Boot Camp: Partition alert message when using Boot Camp Assistant - Apple Support . According to that article, the error comes when there are more than the these three partitions: OS X, Boot Camp, and OS X recovery. Running a "diskutil list" on Terminal, I find that I have 3 partitions: the OS X partition, the Recovery partition, and an "EFI" partition. My questions are: Is that EFI partition keeping Bootcamp from running windows?? If I remove the partition, will it cause difficulties down the road? CAN that partition be removed? Thanks for any thoughts you may have! UPDATE: ISSUE FOUND! Bootcamp does not work on HDD greater than 2.2 TB in size, and my new disk is a 3 TB drive.