Windows 8.1 64-bit ISO Not Recognized in Bootcamp

@Loner T

The USB thumb drive is USB V2.0.

I've downloaded the ISO 3 times using the mediacreationtool.exe and checked the byte count (I didn't do a checksum because I didn't know what to compare it to on OS X coming from a Win 7 system). I tried transfering it between systems using Gb Ethernet, a USB thumb drive and WiFi. In any case, the file size was identical between source and destination 2,662,137,856 bytes (2.66 GB on disk), not very accurate I know.

I can open each ISO on the Mac using the Finder with no problems. I looked around for any text that would identify this as a 64bit vs a 32bit version of Windows. Nothing.

Thanks Loner T! I'll try the mds5 hash too.

I spent an hour on the phone with Apple tech support. Conclusion: "Call Microsoft." They said, "You obviously have the wrong .ISO file." They said that transferring it between systems via Ethernet was prone to errors for large file sizes and said to do it via a USB thumb drive. I did the transfer with a thumb drive with the same result in BCA. I copied it again with the same result. That's when they said to call MS.

I spent two hours on the phone with Microsoft (OMG were they bad, 2nd worst tech support experience in about 500 hours of experience wasting my life on tech support calls for Windows) Conclusion: "Call Apple, only Apple would know if you have the right version of Windows to install on their systems." When I pressed to determine whether I'd purchased a full version vs. an upgrade and whether there was any way to determine if it was 64bit and whether I'd used an official download procedure, they said they have no idea and transferred my, twice. Finally, the answers were: yes you have the right file, yes its 64 bit, and yes mediacreationtool.exe is THE official method to get the .iso file, then they said to call Apple.

Third hour on phone with Microsoft, this time to the Microsoft Store tech Support, they TRIED to give me a refund, but they couldn't figure out how to do it. There was a language barrier. They said to login to the mswos.com site and click the submit button. No matter how many times I told them there was no submit button, they kept telling me to click it.

Regarding their refund process at the msows.com website...

MS: "Do you see the button now?"

Me: "No"

MS:"OK, now click it"

Me: "There is no button to click!"

MS:"OK, do you see it? Now click it!"

repeat for 30 minutes

She took remote control of the system, 15 minutes later,

MS:"Apparently, there is no button."

My plan is to buy a shrink-wrapped, full version of Windows 8.1 with DVD and create an ISO from that. I may have tossed all my systems out the window by then however... My wife is questioning my wisdom that the iMac is better than Windows and requires less tweaking and has fewer support problems because I've been on the phone to support for a total of 7 hours since I received it to replace the older iMac. Please no comments on this, things will devolve into a flame war. They're both good systems in their own special way...

@alexjacobsen That's a shame nobody responded to your post!

Your .iso file seems to be a combined 64-bit/32-bit file, which causes all kinds of issues. You can verify it by using a PC and running teh ISO. If it prompts you for OS selection, then it is a combined ISO. The current size you have seems to be off as well.

This is from an ISO (CDR) created from the physical DVD of W8.1 dual-DVD Retail pack (not the Pro edition).

Stuck in the same deep ****.. Apparently the iso-file is for both 32- and 64-bit...What if you use a trial install from 123myIT that works, and then you upgrade your version when running that trial in windows mode...? I will try tonight...

It should work. The Upgrade does not need BCA. Boot into the Trial version of Windows and insert the dual-mode ISO and run the installer. Make sure you use your Product Key and activate after the upgrade.

IIRC, you need to boot in EFI mode to launch the 64-bit version of the install....

iStir wrote:

IIRC, you need to boot in EFI mode to launch the 64-bit version of the install....

I have a Hybrid MBR boot using BCA on a 2012 13" MBP using a 64-bit DVD (my W8.1 Retail package had two separate DVDs, one each for 32-bit and 64-bit). EFI boot on non-GPT disks or preUEFI Macs causes problems.

I should have been more specific: one needs to boot in EFI mode after burning the .iso file on a DVD in order to launch the 64-bit install. This means a DVD drive is required.

I don't recall being able to choose EFI-install, just the size of the partitions. I have a macbook Air early 2014. I used a w7, 64-bit only free .iso from how-to-geek which worked with no hassle at all. Those found on 123myIT did not because those i tried was 32/64-combos...I then upgraded to 8.1 with my purchased key from microsoft. Took a few hours ?!?! Had no sound and and a dim screen which was impossible to get any brighter. After downloading the upgrade for BootCamp, which you install on the "Windowsside" everything works quite OK... Tried the trackpad++ but it refused to install so I left it out. Still works fine but no pince zoom but i can live without that...

Still have some funny issues with the screen going less bright randomly....!? I do think that the screen looks better on the Mac-side in the same applications... Deeper colours and more contrast but nothing extreme....the 2-fingerscrolling is so much better on the Mac-side. Windows feels jumpy...

But I'm a happy camper so far.... I now have office 2013 which is better then 2011 by miles....

Thanks, RoberthUmea for posting back. Noted for future reference.

Faced both widely reported problems -

- iso file not recognized by BC Asst.

- BC Asst. gets stuck copying files

Here's what I found and successfully installed Win 10 on MB Pro early 2015

- Forget the iso from MS website

- instead make the USB installation media from MS website

- Use Disk Utils in Mac to create image .cdr from the USB installation media and rename to .iso. This iso file will be recognized by BC Asst.

- Use BC step 1 to create bootable USB stick. When it gets stuck, wait for about half an hour and stop the process.

- Now compare the contents of the iso file and the USB stick. If same, fine, use the stick to install Windows using steps 2 & 3 of BC Asst.. If they are not the same, never mind. BC Asst. has already made the stick bootable. Just manually copy all the files from the iso to the stick and proceed for installation with steps 2 & 3 of BC Asst.

- Once the 2 problems are overcome, installation is a breeze using BC Asst. steps 2 & 3.

Spent many frustrating hours. Wonder why Apple is not doing anything to sort out these obvious issues with BC Asst. I'm sure they can sell lot more Macs if Windows can be easily installed.

Hope this helps everyone else with the same issues........

Windows 10 runs like a champ on my MB Pro. Lightning fast. Very fast bootup. Edge browser is a treat to use......... MS has a winner here for sure.

This seems promising! However, can you be more specific when you say: "instead make the USB installation media from MS website"

Every time I try to find the installation media tool on the MS website, it redirects me to download windows 10. Am I doing something wrong? Do you have a direct link to the USB Installation Media creation tool?

Thanks!

You have to download Media Creation Tool from MS. I got it at https://www.microsoft.com/en-in/software-download/windows10

Run the tool and select - Create installation Media for another PC

On 3rd screen select - USB Flash Drive, have your media inserted and press - Next. Your installation media will be created with Win 10