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Boot Camp Quick Tip: Installing on High Capacity Disks

Mac owners using disks that exceed 2.2TB may find it difficult to set up a Windows disk using Apple’s Boot Camp assistant. The root cause of the problem is that the Boot Camp Assistant uses the FAT32 format when setting up a Windows disk. The end result will be an error message (also seen in the image below) that states:

“The startup disk cannot be partitioned or restored to a single partition.

The startup disk must be formatted as a single Mac OS Extended (Journaled) volume or already partitioned by Boot Camp Assistant for installing Windows.”BootCampAsstThe Solution
To work around this limitation, before you run the Boot Camp Assistant you can manually create a FAT32 partition that is 2TB or less, using the OS X Disk Utility. You can learn more about partitioning in Disk Utility by reading this document if you are running OS X version 10.6 to 10.10, or this document if you are running 10.11-10.12, or this document if you are using 10.13 or later.

Afterward you can launch the Boot Camp Assistant and use the built-in features to create a Windows installation disk on the new partition and also to download the Boot Camp drivers. Once you boot to the Windows installation disk, you can use the Disk Management application to reformat the disk — choose the NTFS format — before proceeding with the Windows installation.

Note: This information is provided as a courtesy. For further support regarding OS X or Windows, please visit or

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  • This process did not work at all. Either:

    A—The third option, Install Windows 7 or Higher, in Bootcamp Assistant, was unselectable (“The startup disk cannot be partitioned or restored to a single partition.)
    B– fiddling with partition sizes DID allow partitioning access in Bootcamp Assistant, but during actual partitioning process, the progress bar got stuck at about 25% and NEVER moved ahead.
    FYI this partitioning process should take no more than a minute or two.

    After much trial and error that I shall not detail here, ..
    WHAT WORKED in getting Bootcamp with Windows 8.1 installed on my OWC 2013 Imac was installing Windows manually:

    Much of the information is obtained from this website:
    Since nuances can occur that are not covered in this outline, please refer to it and other sites searching “install Windows Manually without Bootcamp” for further details.

    1–Delete the software from the FAT32 USB disk that was created from the Bootcamp Assistance creation process
    2– Use Bootcamp Assistant to download ONLY the Windows Support Software to the FAT32 USB stick.

    3–Download UNetbootin from
    (versions for earlier Mac OS like Mountain Lion are still available there)

    4–Run UNetbootin and burn the Windows install ISO image to the FAT32 USB disk.

    5 — In Disk Utility program found on the iMac, partition the Mac hard drive adding a MS DOS partition (bigger than 2TB is fine)

    6–With the FAT32 USB still in its slot, turn off, then turn on the iMac.
    As it starts up hold down the OPTION key (The ALT key if using standard keyboard).

    7–Startup disks should display, among them: Macintosh, Windows and EFI
    Select the disk that says EFI boot (this is the FAT32 USB stick)

    8–The iMac should start into a Windows setup/ install screen. Follow the steps.

    9 –At some point BootCamp drivers should start to install automatically.
    if not, when the desktop icons appear, and Windows has finished its install processes, navigate to the FAT32USB drive, open the Bootcamp folder and run the setup(setup.exe)

    11– After the Bootcamp driver install is complete, VICTORY

  • I have this problem with 4gig electra SSD inside of just purchased Mac 27″ 2013 Sierra (10.12.6) from OWC.
    Either Bootcamp option is greyed out
    or if I partition in Disk Utility as per article, can only delete that portion in Bootcamp Assistant

    So I have come here to see if a solution is working

    • We would encourage you to reach out to our Technical Support staff for assistance!

      Our telephone support team can be reached at (800)275-4576 (US only) or (815)338-8685 (International), and are available between 8:00AM-6:00PM [CST] Monday-Friday.

  • Same here its not working
    im using Mojave 10.14.4
    Imac 2017

    omars-iMac:~ omartechz$ diskutil list
    /dev/disk0 (internal, physical):
    0: GUID_partition_scheme *2.0 TB disk0
    1: EFI EFI 209.7 MB disk0s1
    2: Apple_CoreStorage Macintosh HD 885.0 GB disk0s2
    3: Apple_Boot Boot OS X 134.2 MB disk0s3
    4: Apple_APFS Container disk3 1.0 TB disk0s4
    5: Microsoft Basic Data BOOTCAMP 107.9 GB disk0s5

    /dev/disk1 (internal):
    0: GUID_partition_scheme 121.3 GB disk1
    1: EFI EFI 314.6 MB disk1s1
    2: Apple_CoreStorage Macintosh HD 120.9 GB disk1s2
    3: Apple_Boot Boot OS X 134.2 MB disk1s3

    /dev/disk2 (internal, virtual):
    0: Apple_HFS Studio FILE +1.0 TB disk2
    Logical Volume on disk0s2, disk1s2
    Unencrypted Fusion Drive

    /dev/disk3 (synthesized):
    0: APFS Container Scheme – +1.0 TB disk3
    Physical Store disk0s4
    1: APFS Volume Macintosh HD 129.3 GB disk3s1
    2: APFS Volume Preboot 45.1 MB disk3s2
    3: APFS Volume Recovery 522.9 MB disk3s3
    4: APFS Volume VM 17.2 GB disk3s4

    omars-iMac:~ omartechz$

  • I have the same problem, this solution is not working. It only gives the option to errase the partition previously created, please help! I bought this disk to be able to have both Mac and Windows in my computer.

    • Hi Jonathan,

      We are looking into this to see if we need to add new information based on new OS behaviors. To confirm, can you tell me what macOS version you are using? Thank you.

  • I tried this, but bootcamp assistant gave me only one options, which is to delete that fat partition, and took me back to the same problem…This solution does not work.

  • Thanks for the tip. I have a 4TB Aura SSD in my Mac Pro (2013). I get the initial screen in boot camp about the “The startup disk cannot be partitioned or restored to a single partition.”. I then followed your instruction to create the partition with disk utility. That was quite straight forward. However ,when I run boot camp assistant again, it only offer the option to delete this partition and reset all to one Big Mac OS partition.

    Please, any help/ideas are welcome.

    • hello, were you able to solve this issue? if you were I will appreciate to share your solution, thanks in advance.