Boot Camp - issues with installing Windows 10 on 2017 iMac

• Run BC Assistant and remove the current partition. Do not use any other method or tool. - Done
• Disconnect all external storage and leave it disconnected - nothing was connected did not plug anything in
• Eject the ISO - deleted and downloaded a new copy
• Run SMC and NVRAM Reset-done
  • How to reset the SMC of your Mac - Apple Support
  • Reset NVRAM or PRAM on your Mac - Apple Support
• Re-run BC Assistant and try to install Windows. - done and got exactly the same result

Windows cannot locate the disk and partition specified in the unattend answer file’s <ImageInstall> setting. Make sure the setting references a valid partitition and restart the installation.

The only step that I had not completed previously was ejecting/deleting the ISO.

Alexanders-iMac:~ alexanderjohnblissgag$ diskutil list

/dev/disk0 (internal, physical):

  #:           TYPE NAME          SIZE   IDENTIFIER

  0:   GUID_partition_scheme            *1.0 TB  disk0

  1:            EFI ⁨EFI⁩          209.7 MB disk0s1

  2:        Apple_APFS ⁨Container disk2⁩    696.0 GB disk0s2

  3:   Microsoft Basic Data ⁨BOOTCAMP⁩        304.0 GB disk0s4

/dev/disk1 (internal, physical):

  #:           TYPE NAME          SIZE   IDENTIFIER

  0:   GUID_partition_scheme            *28.0 GB  disk1

  1:            EFI ⁨EFI⁩          314.6 MB disk1s1

  2:        Apple_APFS ⁨Container disk2⁩    27.7 GB  disk1s2

/dev/disk2 (synthesized):

  #:           TYPE NAME          SIZE   IDENTIFIER

  0:   APFS Container Scheme -           +723.7 GB disk2

                 Physical Stores disk1s2, disk0s2

  1:        APFS Volume ⁨Macintosh HD - Data⁩  170.2 GB disk2s1

  2:        APFS Volume ⁨Preboot⁩        326.0 MB disk2s2

  3:        APFS Volume ⁨Recovery⁩        613.8 MB disk2s3

  4:        APFS Volume ⁨VM⁩           2.1 GB  disk2s4

  5:        APFS Volume ⁨Macintosh HD⁩      15.1 GB  disk2s5

  6:       APFS Snapshot ⁨com.apple.os.update-...⁩ 15.1 GB  disk2s5s1

/dev/disk3 (disk image):

  #:           TYPE NAME          SIZE   IDENTIFIER

  0:              CCCOMA_X64FRE_EN-US... +6.2 GB  disk3

I was able to create the exFAT partition and copy the contents of the ISO and the Windows support files to it. When I rebooted I did not have the option of selecting the exFAT partition. I could not find a way to make that partition bootable. If I tried booting up to Windows BC installer I get the “we couldn’t create a partition or locate an existing one ...” error.

Well that was a bust. I had to go back to High Sierra and Bootcamp wouldn't even run. I upgraded to Mohave and got exactly the same issue I started with "Windows cannot locate the disk and partition specified in the unattended answer file’s <imageinstall> setting.  Make sure the setting references a valid partition and restart the installation.". It deleted the OSXRESERVE partition when it restarted so I manually created that partition. Redownloaded everything and saved it to that partition. I still do not see any Autounattend.xml files that I could edit. Is there somewhere that there is a sample coding for that? People have gotten this to successfully install, right?

Loner T - thank you so much for all of your help!!! This worked and we have Windows up and running great. I really appreciate your knowledge and guidance on this I would not have been able to figure this out on my own.

That is the problem. Once the installation stops - the computer restarts. If I go back to the Mac OS the OSXRESERVED partition disappears and all that I can see is the BOOTCAMP partition.