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[GUIDE] Dual-Boot for Windows 10 and macOS on the same disk (Windows installed first, macOS installed first, empty drive)


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All-in-One Dual-Boot Guide for all scenarios

(from Sierra 10.12 up to Big Sur 11)

(should work with Windows 8 and earlier versions of macOS but they're untested)

 

When you have Windows installed first and don't want to lose all your data

When you have macOS installed and want to install Windows on a new partition

When you have an empty disk and want to install the two OS

 

  1. Install macOS when Windows 10 is already installed
  2. macOS installed first
  3. Installing on an empty drive

 

Important note: This will ONLY work if your system is in GPT (GUID)-UEFI mode (not MBR-Legacy)

 

What you’ll need:

  • A GPT-UEFI Windows 10 installer USB
  • A macOS USB Installer
  • Working Clover or OpenCore folder

 

As always, a backup is recommended

 

1.     Install macOS when Windows 10 is already installed

So the problem is that the Windows EFI is 100 MB, not 200 MB so the macOS Disk Utility will fail when creating the new APFS partition for macOS, we need to resize the EFI first

 

  • Win + R, open “diskmgmt.msc” (Create and format hard disk partitions)
  • Right click, Shrink your Windows drive to create unallocated space for macOS (do not create a new partition yet)
  • Boot from the Windows installer USB, click “Repair your computer”
  • At “Advanced options” select “Command Prompt”
  • Write the following:
diskpart
(this is the Windows partition manager)

list vol
(note down your Windows partition letter. Default is C:)

list disk
(will list your drives)

Now select your Windows drive (for example 0”)
sel disk 0

list part
(will list your partitions on the selected disk)

select your EFI (System, 100 MB, for example 1”)
sel part 1

delete partition OVERRIDE
(this will delete your EFI)

create partition efi size=200
(this will create the new EFI partition with 200 MB size)

format quick fs=fat32
assign letter=B
(assign a letter to your EFI in order to manage it)

exit
(we can exit from diskpart now)

bcdboot C:\windows /s B:
(this will re-create the EFI files for Windows)

exit
  • That’s it, restart the system and boot to Windows again
  • Open “diskmgmt.msc” again, now create a new partition for macOS from the remaining Unallocated space (name MAC, format ExFAT)
  • Now boot from the macOS Installer USB and format the MAC partition to APFS with Disk Utility
  • Install macOS on that drive
  • After installation finished boot the installed macOS with your USB
  • After arriving to desktop mount your USB’s EFI and copy the Clover or OC folder to desktop (BOOT folder isn’t needed)
  • Remove the USB and now mount your system EFI
  • Copy the Clover or OC folder to the EFI folder
    • Note: if using OpenCore, in config.plist set Misc/Security/BootProtect to “None”
  • Restart the system, you’ll see that Windows will automatically boot, so we need to make Clover or OC to default bootloader
  • Open cmd in admin mode and type:
bcdedit /set {bootmgr} path \EFI\CLOVER\CLOVERX64.efi

or if using OC

bcdedit /set {bootmgr} path \EFI\OC\OpenCore.efi

Note: This will tell the Windows bootloader to not load the original "bootmgfw.efi", but our own Clover or OpenCore loader instead, then Clover or OC will load "bootmgfw.efi" instead

 

  • That’s it! After restart our bootloader will start and we can select Windows or macOS.

 

 

2.     macOS installed first

  • Open “Disk Utility”, click “View” -> “Show All Devices”
  • Click on your drive’s name, “Partition”, add a new partition for your Windows by resizing (MS-DOS, name WIN)
  • Ensure you have working OC or Clover in your EFI
    • Note: if using OpenCore, in config.plist set Misc/Security/BootProtect to “None”
  • Boot from the Windows installer USB
  • Inside Win installer, format the “WIN” partition created in macOS Disk Utility
  • Install Windows on that partition
  • At Windows desktop open “cmd” in administrator mode and type
bcdedit /set {bootmgr} path \EFI\CLOVER\CLOVERX64.efi

or if using OC

bcdedit /set {bootmgr} path \EFI\OC\OpenCore.efi

Note: This will tell the Windows bootloader to not load the original "bootmgfw.efi", but our own Clover or OpenCore loader instead, then Clover or OC will load "bootmgfw.efi" instead

 

  • That’s it! After restart your bootloader will start and you can select Windows or macOS

 

3.     Installing on an empty drive

  • Boot the macOS Installer
  • In Disk Utility, click “View” -> “Show All Devices”
  • Click on your drive’s name, “Delete”, Create a new APFS drive for macOS
  • Click on “Partitition”, add a new drive for Windows (MS-DOS FAT, name WIN)
  • Install macOS on the APFS drive
  • After installation is completed, mount system EFI and copy Clover or OC folder to the EFI folder (just the OC or CLOVER, “Boot” isn’t needed, if there is no EFI folder in the EFI partition, create one)
    • note: if using OpenCore, in config.plist set Misc/Security/BootProtect to “None”
  • Remove the macOS installer and boot from Windows installer USB
  • Inside Win installer, format the “WIN” partition created in macOS Disk Utility
  • Install Windows on that partition
  • At Windows desktop open “cmd” in administrator mode and type
bcdedit /set {bootmgr} path \EFI\CLOVER\CLOVERX64.efi

or if using OC

bcdedit /set {bootmgr} path \EFI\OC\OpenCore.efi

Note: This will tell the Windows bootloader to not load the original "bootmgfw.efi", but our own Clover or OpenCore loader instead, then Clover or OC will load "bootmgfw.efi" instead

  • That’s it! After restart your bootloader will start and you can select Windows or macOS

 

 

 

Notes:

  • After NVRAM reset Windows will automatically boot (because of the Boot/bootx64.efi). Simply restart the system to get back to your bootloader
  • If you're getting errors when formatting in Windows installer:
    • Some errors just because of the 200 MB "non-Windows" EFI, try to ignore them and start the installing. If it'll start, then no problem, no need for any other actions
      • If not working, then try the followings:
        • Unplug all external drives (except the installer)
        • Delete the WIN partition and re-create that from the unallocated space (if you have CLOVER or OC inside the EFI, make a backup first, it's possible that Windows will re-create the EFI and delete them)
  • If you want triple-boot with Linux, create a new partition by resizing the Mac or Win partition, make sure the Linux won't re-format the EFI, in BIOS boot order let "Windows Boot Manager" be the first, then you can select Linux, Win, Mac from Clover. (OC untested) Tested with Fedora 30
  • BitLocker isn't tested. I suggest you to disable it for the time of doing the setups
  • If you mess up the "bcdedit /set ..." line, don't worry, it'll boot Windows automatically even if you messed that up. This is why we need to leave the original "Boot" folder alone
Edited by kushwavez
Added note to Windows drive letters
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