Note the following regarding user TAbdiukov's question which has a links to this question.
This question is about installing Windows 10 on 2011 iMac to achieve a macOS High Sierra / Windows 10 dual boot arrangement. You may be able to adapt my answer to work with a different 2011 or older Macs, if the Mac has received the firmware update which allows booting from ExFAT volumes. The 2011 iMac, used to test my answer, received this firmware update when High Sierra was installed. Also I make no claim that my answer will work with any Linux releases or any Windows versions other than 64 bit Windows 10.
Note the following regarding fdmillion's answer to this question
User fdmillion's answer requires a Mac that can BIOS boot from an USB drive. The only 2011 Macs which can BIOS boot from an USB drive are the MacBook Air and Mac mini models. No Mac models older that 2011 can BIOS boot from an USB drive.
Staring in 2015 Apple starting omitting BIOS code from the firmware which ended the ability to BIOS boot from any type of drive.
Apple does not support Boot Camp Assistant installations of Windows 10 on 2011 and earlier iMac models. The exact list of supported Mac models is given below.
The following Mac models support 64-bit versions of Windows 10 when installed using Boot Camp.
If you have one of the models listed below, then you should use the Boot Camp Assistant to install Widows 10.
- MacBook Pro (2012 and later)
- MacBook Air (2012 and later)
- MacBook (2015 and later)
- iMac (2012 and later)
- Mac mini (2012 and later)
- Mac mini Server (Late 2012)
- Mac Pro (Late 2013)
I have read where others have successfully used the Boot Camp Assistant to create a Windows flash drive installer. This was accomplished by first editing a
.plist file contained within the Boot Camp Assistant software. I have the following problems with doing this.
- The Boot Camp Assistant software has to be hacked in order to create the Windows installer.
- The resulting flash drive installer defaults to a Windows installation that uses the EFI boot method. Apple did not officially start supporting this method of booting Windows until after the 2011 model year. I have always assumed the Windows Support Software, supplied by Apple for my Mac, was designed only for the legacy BIOS boot method of installation.
I have no problems EFI booting the USB Windows installer, but I still want to install Windows to use the BIOS boot method.
Here is what I wish to accomplish.
- Install Windows 10 Pro 64 bit. I have downloaded the latest Windows 10 (Version 21H1) iso file.
- Install Windows 10 into a newly formatted volume. I do not want to first install an earlier version of Windows and then upgrade to Window 10.
- Boot Windows using the legacy BIOS boot method.
- Use only one partition on the first internal drive (
disk0) for the Windows files. The single internal disk in my Mac uses a 512 byte sector size.
- Install Windows using the latest version of macOS. Currently, this would be High Sierra (macOS 10.13.6).
I would desire to preform the installation without any of the following.
- No third party software
- No optical (DVD) drive
- No Boot Camp Assistant
- Without disabling System Integrity Protection (SIP).
I would prefer not having to boot to macOS Recovery via the internet, built-in recovery or an USB flash drive macOS installer. But, since macOS Recovery is not a third party tool, I am not opposed to its use.