Solved How does Windows know which installation to boot?

I am cloning my current Windows partition from one SSD to another. I am not moving the EFI partition. I will still use the EFI partition on the first SSD. How does the system know to start the Windows installation on the new SSD?

When using Linux, on the EFI partition there is a file that contains the system partition UUID. You can edit this file to point to a different partition by changing the UUID. For Microsofts EFI partition I don't see any equivilent to update.

How can I tell the EFI partition to start the Windows installation located on the new SSD?

Windows doesn’t “detect” the correct installation — it simply loads whichever EFI partition the BIOS points to. But because the cloned BCD still references the original disk’s identifiers, you must either boot with the old disk disconnected or rebuild the BCD so the new EFI partition correctly targets the new Windows installation.

Even after rebuilding the BCD on the new drive, having 2 efi partitions with 2 bootloader as well as duplicate hardware identifiers connected at the same time is a recipe for trouble in the future IMO.

glasskuter said:

Windows doesn’t “detect” the correct installation — it simply loads whichever EFI partition the BIOS points to. But because the cloned BCD still references the original disk’s identifiers, you must either boot with the old disk disconnected or rebuild the BCD so the new EFI partition correctly targets the new Windows installation.

Even after rebuilding the BCD on the new drive, having 2 efi partitions with 2 bootloader as well as duplicate hardware identifiers connected at the same time is a recipe for trouble in the future IMO.

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I don't intend on having two EFI partitions. Once everything is complete I want the EFI partition only on the first SSD. Windows will only be installed on the second SSD.

My end goal is to have UEFI and Linux on the first SSD and Windows on the second SSD. When the system boots, I want to see the grub loader so I can choose between Linux and Windows.

If Linux Mint was installed after Windows, Grub2 which Linux Mint uses should have put an entry in Windows boot manager. Grub provides the menu that allows you to choose Windows or Mint at startup. Grub (Mint or Ubuntu) should be the first entry in bios boot sequence with windows second, inorder for the menu to display. You do not need to move anything to get what you want.


This utility comes with Mint. They can help you fix grub.

An EFI partition may have one or more Boot Managers that will transfer the boot sequence to a boot loader on same drive or even on different drive.
Grub is a Linux boot manager and it can have more than one option to boot from, A Linux as default and one may be a Windows.
My system has, on same drive, windows and Lubuntu but I choose to have the two boot managers on the EFI partition and only Lubuntu under Grub.
My default boot is Windows and when I want to boot Lubuntu I launch the boot menu under POST (F12) on my computer.

I accomplished my task. I've swapped my OSes and both are still bootable without resorting to the BIOS boot menu.

When I cloned my Windows drive to the second SSD it brought the UUID with it. I didn't expect that. Because of this I didn't need to do anything as I was using a copy of the UEFI partition that I had before. I did have to update the UUIDs on the Linux side of things, since I had a file copy and not a disk image.