EFI partition preventing installation of Windows 7 on Yosemite?

Discussion in 'Mac Basics and Help' started by SnarkyBear, Jan 7, 2016.

  1. SnarkyBear, Jan 7, 2016
    Last edited: Jan 8, 2016

    SnarkyBear macrumors member

    SnarkyBear

    Joined:
    Apr 24, 2014
    #1
    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:
    1. Is that EFI partition keeping Bootcamp from running windows??
    2. If I remove the partition, will it cause difficulties down the road?
    3. 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.
     
  2. mfram macrumors 65816

    Joined:
    Jan 23, 2010
    Location:
    San Diego, CA USA
    #2
    EFI is used for boot. It must be there. Sounds like a bootcamp bug to me.
     
  3. chscag macrumors 68000

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #3
    As stated, the EFI partition must exist or your Mac will not boot. The error message you received is deceiving since it doesn't mean what it says. What it's really telling you is that you do not have enough continious free space on the drive to create a Boot Camp partition. The key word there is "continuous" even though it may seem you have enough space.

    In other words, your drive is fragmented (yes, OS X does fragment).

    There are two ways to resolve this: 1. Erase the drive, reinstall, recover your data from backup. Fragmentation will be gone. 2. Use a third party app such as iDefrag.
     
  4. SnarkyBear, Jan 8, 2016
    Last edited: Jan 8, 2016

    SnarkyBear thread starter macrumors member

    SnarkyBear

    Joined:
    Apr 24, 2014
    #4
    That would be extremely frustrating if the disk needed defraging, since the hard drive is only 3 days old and everything is a clean install.
    However, the only thing I can lose by running a defrag is time, so I will give it a shot.

    UPDATE: I ran disk defrag, compressing my 250 MB of Data onto the very edge of a 3 TB HDD. The error still remains.
     
  5. SnarkyBear thread starter macrumors member

    SnarkyBear

    Joined:
    Apr 24, 2014
    #5
  6. chscag macrumors 68000

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #6
    OK, I wish you had given us the disk size in your first post. You're correct... that's because it (Boot Camp) initially formats the partition as FAT-32 and FAT-32 is limited to ~2 TB. Anyway, glad you figured it out.
     
  7. SnarkyBear thread starter macrumors member

    SnarkyBear

    Joined:
    Apr 24, 2014
    #7
    I didn't mention HDD size initially because I did not know it was important. Likewise, if I had known the 2 TB limitation, I would have put in a smaller drive.

    I am SO glad that I found out about this now--I was planning on getting a new iMac later this year. I would have been VERY frustrated to spend an extra $400 on a 3 TB fusion drive only to find out that I couldn't install Windows!
     

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