Mac Pro 5.1 2012

bootcamppartition

I am trying to install Windows via Boot Camp Assistant and get the following message:

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.

In Disk Utility only one unpartitioned drive is displayed.

In Terminal, the output of distutil list is:

/dev/disk0 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Install macOS High S... 90.9 GB    disk0s2
   3:                  Apple_HFS bup macpro              364.0 GB   disk0s3
   4:                  Apple_HFS Untitled                544.7 GB   disk0s4

/dev/disk1 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *4.0 TB     disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:                  Apple_HFS Macintosh HD            4.0 TB     disk1s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS Crucial 500gb           499.2 GB   disk2s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk2s3

Disk0 is used for TM backup. Disk1 is main HD, where Windows is to be installed. After Windows is installed I intend to format and clone disk2 from disk1 and install it in the Mac as the boot drive. I only installed HS and network settings on disk2 to confirm the partitions would be set up.

The question is, how do I merge/delete the partitions on disk1 to satisfy Boot Camp Assistant?

Best Answer

Below is a response to your statement: "If my Internal drive is not set up incorrectly, why is BCA preventing the install."

Apple does no officially support Windows 10 on your Mac, but Microsoft does. Say you first installed Windows 7 with Apple's Window Support Software. Now, if you upgraded to Windows 10, then Windows 10 would be using the Windows 7 drivers provided by Apple. So, there is no reason why you can not install Windows 10 with Apple's Windows Support Software written originally for Windows 7.

Below is an answer to the question: "If my Internal drive is not set up incorrectly, why is BCA preventing the install?"

The Boot Camp Assistant installs Windows at the end of a drive. This is physically impossible to do with your disk1. The sector numbers for your 4 TB drive are to large to be stored in a legacy MBR partition table used to BIOS boot Windows.

Furthermore, you probably would have to remove disk0 in order to install Windows on your Mac. This requirement was published in early editions of the Boot Camp Installation & Setup Guide. For example, the paragraph below was taken from Boot Camp - Installation & Setup Guide (Mountain Lion) Mar 14, 2013.

If you have a Mac Pro with more than one internal disk and you want to install Boot Camp on a disk that isn’t in the first hard drive bay, remove the drives in the lower- numbered bays. You can reinstall the drives after you install Boot Camp.

I do not think I understood the rest of the questions you posted in your latest comment.

I would try installing Windows without using the Boot Camp Assistant. The first step would be to burn the Windows ISO file to a DVD. You will also need a flash drive for the Windows Support Software from Apple. You can omit the DVD and use the same flash drive to hold the Window ISO files, but this makes the installation procedure more complex.