Windows 10 1709 (Oct 2018 ver.) migration from MBR HDD to GPT SSD (or another HDD)

You purchase a new lightening-fast SSD or super-sized HDD, and it's time to copy your Windows system to the new storage!

If your original HDD and new SSD are both partitioned with GPT, simply use a free version partition management software from EaseUS or Minitool. Free versions still support cloning a partition from GPT to GPT, or MBR to MBR.

However, if your old disk uses MBR and want to get benefits of the fancy GPT partition on your new disk, it can bring some headache. The easiest way is to purchase a "Pro" version of the previously mentioned commercialized software. Only paid versions support migrating (or cloning) a system partition from MBR to GPT.

If your budget is limited and you do not want to pay $$ for one-time system migration, then this is the article for you! There're simple steps.

1. Attach the new drive, detach the old drive, and create EFI partition on the new drive.

Boot with the Windows 10 installation media, and clean-install Windows on your new drive with GPT partition. This will create an EFI partition automatically on your new drive which allow to boot on UEFI/GPT mode.

Instead of installing the new Windows, you can simply try to manually partition the new drive for Recovery (500MB, NTFS, OEM Partition), EFI (100MB, FAT32, EFI), and Windows (NTFS). EFI partition will be used to install Windows booting information after cloning the old windows to the new windows partition.

2. Attach the old drive and clone the old Windows NTFS partition.

The easiest way is to boot with the old windows, install EaseUS Todo Backup free version, and clone the old drive (C:) to the newly created Windows partition of the new drive (overwrite). You don't need to use "System clone" which is supported only by paid software. Just use "data clone" function in the free version.
In fact, this will ruin the clean-installed windows on the new drive because you overwrite the windows partition with the old system. You cannot boot with the copied partition YET.

You can do this with Clonezilla, ntfsclone, Minitool, or any other disk cloning software.

3.Detach the old drive again, and recover the booting of the new drive.

Once the cloning is completed, it's time to recover the booting from the newly copied volume on the new drive. When you tried to boot with the new drive, it'll simply throw an error message.

Boot with the Windows Installation Media USB, select Repair, go to Advanced, and open Command Prompt. The prompt shows up with X:\ as a default drive.

Type these commands to assign a drive letter for EFI partition:
X:\> diskpart
list disk
sel disk 0  // if 0 is the new drive
list vol
sel vol 3 // if 3 is the EFI partition with 100MB FAT32
assign letter=G:
exit

Then, format G with the following command:
X:\> format G: /fs:FAT32

Now, you have to install EFI partition with a new boot for the cloned Windows partition.
Type the following command:
X:\> bcdboot C:\windows /s G: /f UEFI

Now your EFI partition is recovered with the cloned Windows.
Unplug the USB and reboot! Windows should be able to boot without any problem.

Once Windows is working well with the new drive, you can attach the old drive if you want to use it for other purposes.