I can't believe this: "Boot Camp only supports Windows 7 or later installation on this platform..."

Unfortunately that didn't work for me. I have the same setup (El Capitan latest version, Windows 10 latest version) and a Mid-2014 Retina MBP, but no luck.

Where did you get the Windows Installer from?

Stas Sagdeyev wrote:

It's been a while... But let's get back to this matter.

If you choose to use the external USB Yosemite path, do not use an external USB HDD, use a flash drive. An external USB/FW disk drive will cause problems.

I spent over a month running 10.10.5 Yosemite from an external USB 3.0 HDD, and encountered no problems whatsoever. I can confirm it works fine on MacBookPro10,1. Obviously, it's slower compared to SSD. However, you say it will cause problems. Would you care to elaborate?

The primary challenge is OS X software upgrades. If you boot from a higher OS X version, and upgrade software (some newer EFI upgrades have been seen), and then switch back to an older OS X version from a different external disk, it can cause peripherals to not work properly. Windows sleep/wake is notorious, Thunderbolt devices can also malfunction.

Concerning Windows 10 installation,

I did perform W7-to-W10 upgrade (which, again, is noted in the initial post), however, for obvious reasons, a clean re-instal, is, eventually, inevitable.

Now, I was able to use Boot Camp Assistant 5.1.4 (500) from my new 10.10.5 Yosemite in order to create a Windows 10 installation USB media.

Then, apparently, BCA 5.1.4 tends to reboot the machine in EFI mode which (as mentioned by Loner T) is not good for MacBookPro10,1.

Trying to find a quick solution, I found an immediate workaround, which may sound as a bit of a trouble but so far is the only way.

After creating an install media in 10.10.5/BCA 5.1.4, I boot back into 10.8.5 (from internal SSD) and run its BCA 5.0.4. I give it just any image it's able to recognise (doesn't matter at all which one) and let it think I'm now gonna install Windows 7 or whatever. As soon as it reboots the machine (and it does reboot in legacy BIOS mode), I insert a previously created Windows 10 USB install media.

Then, we just install Windows 10...

This is also used when W7 came out and users wanted to stick to XP, they would eject the W7 media with Alt/Option and insert XP disk, when booting to get past the BCA checking for XP vs W7. Glad to see it working. Macs are forcing EFI, even though W10 will work on BIOS/MBR mode. It is interesting to see M$ supporting both, but Macs have switched from EFI 1.1 (preUEFI) to UEFI and will only support W8.1/W10 on newer Macs. Please ensure you have good back ups.

Thanks for posting your findings.

A USB device with 32GB or larger confuses Windows (and BCA) whether you are installing on an external USB or an internal PCIe/SATA (or TB) disk. OSX Updates are a bit smarter and will let you update USB-based OS X installations, but recognize that version control is not supported on such devices. USB HDDs in contrast will work with version controls built into OSX. W10 is a lot better than W8.1 in this regard.

The EFI directory on a GPT usually contains the OSX Firmware, and in some cases, the Windows BCD and Bootmanager EFI (this is Mac-model specific). I have seen EFI updates fail because the booted media came from an older OSX version and refused the firmware, but booting from internal disk with proper firmware allowed it to work. Recovery from EFI update failures usually requires a trip to an Apple Store or an AASP (which can be painful and time-consuming).

Hi Loner T,

I downloaded the ISO directly from the Microsoft website.

By the way, I downloaded the Windows 8 ISO from Microsoft, and that didn't work either. Then I downloaded the Windows 7 ISO, and that worked, but I couldn't upgrade because the Windows 10 license key I had purchased didn't work with the upgrade!

Any help would be appreciated.

Thanks

If you have W7 installed/activated, your W10 upgrade is Free. If you purchased W10 Product Key, you can do a clean install of W10. If you want to start a new discussion with specific of your W7->W10 or W10 installation issues, it may be easier to address them.

As I only downloaded the Windows 7 ISO, it wasn't activated. I actually did install Windows 7 with Bootcamp, but when I used the Windows Media Center (or whatever) to upgrade to Windows 10, it asked for my Windows 10 license key (which I purchased), but didn't accept it, saying that the license key is not for this version of Windows. (Sigh, Microsoft.)

But that's not related to Bootcamp though. How can I use Bootcamp to do a clean install of Windows 10?

Please see Use Windows 10 on your Mac with Boot Camp - Apple Support .

These may also help.

How to install Windows using Boot Camp - Apple Support

https://help.apple.com/bootcamp/assistant/6.0/

https://help.apple.com/bootcamp/controlpanel/5.1/

I've been following these threads and you seem really knowledgeable with bootcamp. I have a lot of experience with boot camp assistant running versions of windows since boot camp was released by Apple, but I've been stumped. I just wiped my volume and installed a clean version of El Capitan (3TB 7200rpm NON FUSION, late 2012 27" iMac). When I run boot camp assistant, it downloads the support software just fine and creates my boot-able Windows 10 usb (that I can option boot to and run the installer) but the main "install Windows 7 or higher" option is still greyed out. I have done the process a few times and no luck. Any reason you can think of causing my boot camp assistant to not recognize everything being ready to start the partition/install process? Thanks!

Also, I have tried to create a separate partition twice formatted in MS DOS (FAT) and EXFAT. When I boot to my windows 10 USB I can start the install just fine, but when I format the proper partition (disk04 WINDOWS) within the installer it still says Windows can't be installed in that disk/partition. What gives?

Can email me at coryvaldez@me.com if you'd like.

Cheers

Please start a new discussion and post the year/model of your Mac. Do not post the serial number.

Unfortunately I've gone through it all and have had no luck. When I select the Windows 10 ISO I downloaded from the Microsoft website, here's what I get:

EDIT: I get the same error message with a Windows 8 ISO, but not Windows 7. (But of course Windows 7 doesn't actually let me upgrade to 10...)

osmanm wrote:

As I only downloaded the Windows 7 ISO, it wasn't activated. I actually did install Windows 7 with Bootcamp, but when I used the Windows Media Center (or whatever) to upgrade to Windows 10, it asked for my Windows 10 license key (which I purchased), but didn't accept it, saying that the license key is not for this version of Windows. (Sigh, Microsoft.)

Your Product key will only allow a clean installation. If your W7 was active, it would let you upgrade to W10.

osmanm wrote:

Unfortunately I've gone through it all and have had no luck. When I select the Windows 10 ISO I downloaded from the Microsoft website, here's what I get:

EDIT: I get the same error message with a Windows 8 ISO, but not Windows 7. (But of course Windows 7 doesn't actually let me upgrade to 10...)

1. What year/model is your Mac?

2. See previous comment about W7 -> W10 upgrade. W7-W10 upgrade is free and during the upgrade process, it provides an embedded key that can be extracted. Your Mac will register with Microsoft, so the same hardware/embedded key combination allows clean re-installation of Windows as well.