iMac 2015 Unable to Boot Camp and Install Windows

I've been going back and forth with a Customer Service guy via phone, but thought I'd throw the question here as well to see if there were others who experienced similar issues and might be able to help.


I own a iMac Retina 5K, 27-in, Late 2014. It used to run Boot Camp with Windows 8.1, which I set up about 1 year ago. It ran fine. But then I decided to try and upgrade to Windows 10 about 3 weeks ago, which did not go well. So decided to erase the partition via Boot Camp Assistant and re-install from scratch.


Now, I can't install Windows at all. I've tried everything. Using a different ISO downloaded from the Windows website. Checked the drives using First Aid. Last night I even fully erased the drives (via terminal in recovery mode, with the assistance of the CS guy) and did an "internet reinstall" of the OS and then tried to boot camp again. No success.


I tried calling Microsoft too, but their stance on the whole thing is "it's on a Mac, this is Apple's problem. bye."


From appearances, Boot Camp Assistant is successfully creating a partition. The system resets in to Windows Setup every time and I go through the setup flow until I get to the "Where do you want to install Windows?" section. I select my Bootcamp partition, format it, and then click next. This is when I get the error message "We couldn't create a new partition or locate an existing one. For more information, see the Setup log files."


If I cancel out of setup and restart back on the OSX side, I can see that the new partitions is in the Windows NTFS format, so it seems ok. I'm thoroughly stumped and frustrated as **** at this point.


Any thoughts? Ideas? Help? Please?


Specs:

iMac (Retina 5K, 27-inch, Late 2014)

Processor 4GHz Intel Core i7

Memory 16GB 1600 MHz DDR3

Graphics AMD Radeon R9M295X 4096MB

iMac (Retina 5K, 27-inch, Late 2014), OS X El Capitan (10.11.4), Windows 8.1

Posted on Apr 1, 2016 3:32 PM

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13 replies

Apr 1, 2016 9:52 PM in response to tingc888

The reason for only the Remove... option to show up, the MBR is in a state that BCA thinks there is Windows. If you have run SMC and NVRAM Reset, connect the USB, power cycle the Mac and hold the Alt/Option key and select Windows (do not select EFI Boot) and run through the steps. If you see an error or unable to complete the installation, please post back.

Have you done step 11 under Install Windows 7 and earlier on your Mac using Boot Camp - Apple Support under Perform a new install of Windows 7 ?

Apr 1, 2016 6:03 PM in response to Loner T

In the past, I had an external monitor plugged in via thunderport (but otherwise powered off).

I just tried running Boot Camp Assistant again with just the WIN Installer USB plugged in only. I got the same error. Other than my keyboard and trackpad (connected via bluetooth), there's nothing else external associated with the iMac.

Apr 1, 2016 6:35 PM in response to Loner T

I only see Remove option (well, "Create a Win 7 or later version install disk", "Download the latest Windows support software from Apple", and "Remove Windows 7 or later version")


Though after the prior failed attempt at setting up bootcamp, I did not re-enter BC Assistant to remove the partition, so I kind of expected this to appear in BC Assistant.... Is it not supposed to?

Apr 1, 2016 7:06 PM in response to Loner T

So I got to the "Where do you want to install Windows?" step and it gives me the error "Windows can't be installed on drive 1 partition 4." Upon viewing details, it tells me "Windows cannot be installed ot this disk. The selected disk is of the GPT partition style." Attempting to format it in the window's setup window doesn't change this.


Also when I created the ISO from the disc, it did not create any of the files listed in step 11. It did, however, create a .dmg in addition to the ISO, which I did NOT click-and-drag in to my USB.

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iMac 2015 Unable to Boot Camp and Install Windows

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