I'm upgrading from a 1TB Samsung 860 EVO to a 2TB Samsung 9100 Pro, but my motherboard has only one M.2 slot. I cloned the old drive using Macrium Reflect and then swapped in the new one. The clone contains the main Windows partition and the other visible partitions, but roughly 2.4GB appears to be missing compared with the original drive. The new drive will not boot, so I'm wondering whether an EFI, recovery, or other hidden system partition was left out. I also tried Macrium's Rescue option to rebuild the Windows boot menu, but it seemed to change the available space on the C: partition instead. What is the correct way to clone the drive and repair the boot setup?
4 Answers
The drive’s authentication label in a vendor utility is not what determines whether Windows can boot. A generic NVMe name or missing vendor verification can be normal, especially with a newer model or a different driver. Focus on confirming that the clone contains the EFI boot partition and that the firmware is booting the new disk in the same UEFI mode used by the old one.
The clone needs to include every partition, not just C:. That normally means the EFI System Partition, Microsoft Reserved partition, Windows partition, and recovery partitions, kept in the same order as on the original disk. Boot from a Macrium or other rescue USB, clone the entire disk to the new drive, expand the main Windows partition into the extra space, and leave the recovery partitions at the end. Once it finishes, shut down completely, remove the old drive, and boot with only the new one installed.
A missing hidden system partition or an incorrect boot record is the most likely cause. The EFI partition contains the files needed to start Windows, and it may not show up like a normal drive. If all partitions were copied, boot from the new drive’s rescue environment and rebuild the boot files there, making sure the system is using the correct UEFI boot entry. Also verify that the firmware is set to UEFI mode and that the new drive is first in the boot order.
So the repair should be performed after swapping in the new drive, while booted from a rescue USB, rather than trying to repair the old installation first?
You can also use a bootable cloning tool such as Rescuezilla or Clonezilla. Clone disk-to-disk from the 1TB source to the 2TB destination and include every partition. Afterward, use a partition editor if necessary to move the recovery partition to the end and extend C: into the remaining space. Double-check the source and destination selections, because choosing them backward will erase the original drive. Disconnect the old drive before the first boot so Windows doesn’t accidentally use its boot files.
I could only find the newest Macrium release on the manufacturer’s site, so I wasn’t sure whether an older rescue environment was still required. I’ll check that I’m cloning the complete disk layout rather than selecting only the visible partitions.