OpenCore Multiboot

# Dualbooting with Windows

  • MBR based Windows installs ARE NOT SUPPORTED by OpenCore at this time, you will need to convert it to GPT.

# Solution 1: If Windows is not picked up automagically, add the following to your config.plist

Misc -> BlessOverride -> \EFI\Microsoft\Boot\bootmgfw.efi
  • Note: As of OpenCore 0.5.9, this no longer needs to be specified. OpenCore should pick up on this entry automatically

# Solution 2: To make Windows get picked up, boot to recovery mode from within Windows

  • make sure you boot windows from OpenCore
    • after loading OpenCore, press space > OpenShell (make sure you have it in Tools and in the config)
    • run map -r -b
    • look for your EFI drive (usually it's in the first lines, watch out if you're a multidisk user, there might be many EFIs)
    • run FSX:\EFI\Microsoft\Boot\bootmgfw.efi where X is the number of the EFI partition with windows bootloader
  • make sure that RequestBootVarRouting is set to True
  • open CMD/PS with admin rights
  • run shutdown /r /o /t 0
    • this will reboot your windows system immediately to Advanced Boot Menu menu
  • select Troubleshoot > Command Prompt
  • it will reboot to WinRE and you'll get to the Command Prompt
  • once in there
    • run diskpart
    • once loaded, send list vol
    • look for your Windows drive letter
      • it may not have the C lettering, but make sure you check the size and other indicatives that points to it
      • if you cannot, just write down the mounted letters with (NTFS) filesystem then explore them one by one to check if it's your windows install
    • look for your EFI partition
      • it should say hidden or system and is usually 100-200MB (some OEM installs make it bigger as much as 500MB)
        • send sel vol X where X is the EFI partition number
      • if you're in doubt
        • send list disk
        • identify your windows disk
        • send sel disk X where X is the disk where Windows is installed on
        • send list part
        • check the partitions, usually the EFI should have 100-200MB (some OEM installs make it bigger as much as 500MB)
        • send sel part X where X is the EFI partition number
      • either way, send assign letter=S
        • S can be anything other than A/B/Y/X and any letter already assigned in the listing before it
    • send exit to close diskpart and return to the command prompt
    • run bcdboot X:\Windows /s S: /f UEFI
      • bcdboot (opens new window) is a utility that installs Windows bootloader in either your EFI or root system partition (of choice)
      • X:\Windows is a path to the Windows installation folder, where X is the mount letter of the Windows partition
      • /s S: is the destination disk that will receive the bootloader, in our case, it's the EFI partition
      • /f UEFI to specify the type the bootloader should be (UEFI Bootloader)
      • This will copy a new bootmgfw.efi file as well as add a new NVRAM Boot entry which hopefully will now appear on OpenCore boot menu.
  • if everything ran without any errors, type exit and it should return you back to the Advanced Boot Menu (or reboot)
  • reboot and check if Windows boot entry has been added

⟵ For Linux booting ⟶