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Tarek

macrumors 6502
Original poster
Jun 25, 2009
393
77
Cairo
Hi there

I know it has been discussed in several threads I've seen before, but I've not really seen an actual step by step guide on how to achieve that or what the requirements are.

I've always had problems when running Windows through Boot Camp because the battery drains really quickly, the laptop overheats, the fans are loud most of the time, and many other issues, and I've read that installing Windows natively through EFI eliminates all those problems.

I recently purchased a 2015 rMBP and I'd like to install Windows 10 natively on it (since I know Windows 7 is no longer officially supported), so can someone please guide me on how to achieve that? I've come across a guide where I have to format the whole SSD and reinstall MacOS and then Windows, but I'd rather avoid that if there is any other way.

I have a Windows 10 ISO which I downloaded from Microsoft's website and I can use that to make a bootable USB.

Thank you for your time, ladies and gents.

EDIT: I just read that Boot Camp installs Windows in EFI mode on MacBooks post 2013. Is that true?
 

maflynn

macrumors Haswell
May 3, 2009
73,478
43,405
I've always had problems when running Windows through Boot Camp because the battery drains really quickly, the laptop overheats, the fans are loud most of the time, and many other issues, and I've read that installing Windows natively through EFI eliminates all those problems.
I think that occurs not because it was installed via bootcamp, but rather because the drivers to properly control and cool the machine are not included.

I used these steps for a full install on my iMac, even though they're for an external drive, just reference to your internal drive where the steps mention the external drive. Also these steps will take your entire drive and dedicate it to windows, be sure that's what you want. That's what I wanted, and it worked flawlessly. I know have a full installation of Windows running on my iMac and no OS X on the internal drive.


Credit to yjchua95

Use this method (a bit windy but definitely works):

Connect external drive to Windows VM. You must have a Windows VM in VMware/Parallels/VBox, or a Windows PC. Any existing Windows environment will do.

What you need:
install.wim file (obtain this from your Windows ISO)

Open elevated cmd.exe (run as admin)

Note: All commands aren't case sensitive, including pathway to files.

Type diskpart
Type list disk
Take note of the disk you want to select
Type select disk 1 (if your disk is Disk 1)
Type clean
Type convert gpt (stop at this point if you're using a drive with a Thunderbolt port)
Type create partition EFI size=100 (skip if installing in BIOS-CSM)
Type format quick fs=fat32 label=EFI (skip if installing in BIOS-CSM)
Type assign letter=S (skip if installing in BIOS-CSM)
Type create partition primary
Type format fs=ntfs quick label=W2G (or any other name you wish for label)
Type assign letter=E
Type exit

Open up File Explorer. In your C drive, create a new folder named WIN2GO.
Put the install.wim file in this folder

Back in cmd.exe:
Type dism /apply-image /imagefile:C:\WIN2GO\install.wim /index:1 /applydir:E:\ (this process will take quite a while)
Type E:\Windows\System32\bcdboot E:\Windows /s S: /f UEFI (use this one for UEFI installation)
Type E:\Windows\System32\bcdboot E:\Windows /s E: /f ALL (use this one for BIOS-CSM installation)

Restart your entire Mac. After the chime, hold down Option and when prompted to select your boot drive, select EFI Boot (or whatever else that comes up for a BIOS-CSM installation).

Proceed installation normally.

After installation, install Boot Camp drivers. Feel free to trash the VM once you're done too.

For best results, use USB 3/Thunderbolt. If you don't have USB 3, use Thunderbolt. If you have neither, stick back to the internal drive

Don’t use a USB stick.

Note: This method involves reformatting the entire external drive.

For Thunderbolt drives, just boot from the Windows USB installer and install directly onto the TB drive. Windows sees TB drives as an internal PCIe connection. However, you must format the TB drive as GPT first.

CAUTION: Windows can only be installed in UEFI flawlessly on Haswell Macs and later. Ivy Bridge and earlier Macs can only run Windows in BIOS-CSM flawlessly. Attempts to boot a UEFI installation of Windows on an Ivy Bridge or earlier Mac will result in driver issues.

UEFI-compatible Macs:
MacBook Air (mid-2013 and later)
iMac (late-2013 and later)
Retina MacBook Pro (late-2013 and later)
Mac Pro (trashcan shape)
Mac Mini (late-2014 and later)

Non-retina MBPs are not UEFI compatible.

WinToUSB basically does the same thing, but doesn’t always work because WinToUSB doesn’t really take into account between BIOS-CSM and UEFI Macs; it only uses one method for all (which may result in boot failures and other problems).
 
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Sincci

macrumors 6502
Aug 17, 2011
284
65
Finland
EDIT: I just read that Boot Camp installs Windows in EFI mode on MacBooks post 2013. Is that true?

It is. You'll just need to open the Windows 10 .ISO in the Bootcamp Assistant and it will install it in a native UEFI/GPT mode without any extra hybrid MBR partitions.
 
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MacBAir

macrumors member
Aug 5, 2016
96
118
Portugal
Did you also install the bootcamp drivers, right?

One thing that could be causing you issues: Recently, I installed win7 sp1 on my 2011 MBAir. After everything was said and done, one core was stuck at 100%, and the fans were going for it.

To my surprise, it was windows update. It took days and days of research in order to find an way to update Windows, because Windows update would get stuck. It is a known issue, and it will happen on every single new Windows 7 installation, some Windows 8.1, and even a few Win10 installations.

It has been this way since a long time. Also, Win10 newest updates are causing chaos in a big, big percentages of computers. It turns out Windows 10 isn't a fast, stable and secure system.
 
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