I recently bought a larger SSD to replace my older, smaller boot SSD. I encountered an issue where the cloned drive would not boot. Fortunately, I did not reformat the older drive and kept that drive installed in my system, so I was able to correct several problems from Windows 10.

Choosing MBR over GPT

The first problem was I had previously initialized the new disk using the GPT partition style. To use the solution to the second problem, and ultimately resolve the entire issue, the cloned disk must use the MBR partition style. To accomplish this, I dismounted the disk using this command:

mountvol B: /P

The /P argument effectively dismounts the drive and unassigns the drive letter.

Then, I removed the existing volumes, and re-cloned the source drive. After the cloning process completed, I verified whether the disk was using the MBR partition style before continuing.

Making the cloned disk bootable

Next up, the second problem: the disk was not bootable. This can be solved without using WinPE. To rewrite the master boot record for the new disk, I used this command:

bootsect /nt60 B: /mbr

You can read about the bootsect arguments here: Bootsect Command-Line Options.

While updating the master boot record allowed the OS to boot from the cloned disk, there appeared to be a third problem after I booted into Windows.

Deactivating the old System Reserved partition

The older System Reserved partition was still Active. I don't know what consequences follow two active System Reserved partitions, but I did not want to find out. I had to deactivate the older partition somehow. This, too, can be achieved from Windows using the diskpart utility:

1. Run: "diskpart"
2. Type: "list disk"
3. Type: "select disk #" (where # was the older disk index)
4. Type: "list partition"
5. Type: "select partition #" (where # was the System Reserved partition index)
6. Type: "inactive"
7. Type: "exit"

I rebooted after this procedure to ensure the new System Reserved partition was being used.

Finally, I had successfully cloned, configured, and booted the new SSD!