Preparing to repair (but NOT the endless loop variety)

Megahertz said:

On an UEFI-GPT, BIOS transfer the boot sequence to the BIOS priority boot manager on a Fat32 Partition and then this boot manager transfer to a OS on a partition (same drive or even to a different drive). On the FAT32 partition you may have one or many boot manager (Linux and Windows etc). On the boot managers on the EFI partition the OS partition isn't identified by a letter (C:) but by a partition ID. This partition ID is created and assigned to the partition when you create it and although you cloned the partition it has a different ID on the target than on the source.
A boot repair will read the C: ID partition and correct it on the boot manger.



After you cloned the HDD
1) EFI - 100M Fat32
2) Reserved - 16M raw
3) C: - NTFS
4) Recovery - 800M NTFS
partitions on the SSD, detach the HDD (SATA or power cable).
Boot from the SSD, open Macrium Reflect and choose to fix the boot loader. It will read the C: ID partition and correct it on the boot manger.
If you still have the SSD that now doesn't boot, you can try to rebuild the EFI partition.
I can give you the instructions.

OK, so I will do that at the first opportunity, which may be this weekend depending if I can get access

Thank you

Do you still has the SSD that now doesn't boot? If so, would you like to try to rebuild the EFI partition?

Megahertz said:

Do you still has the SSD that now doesn't boot? If so, would you like to try to rebuild the EFI partition?

No, I did a fresh install just to eliminate the possibility that it might be a faulty SSD. "Biostar" is not a brand I had ever heard of before.

Megahertz said:

On an UEFI-GPT, BIOS transfer the boot sequence to the BIOS priority boot manager on a Fat32 Partition and then this boot manager transfer to a OS on a partition (same drive or even to a different drive). On the FAT32 partition you may have one or many boot manager (Linux and Windows etc). On the boot managers on the EFI partition the OS partition isn't identified by a letter (C:) but by a partition ID. This partition ID is created and assigned to the partition when you create it and although you cloned the partition it has a different ID on the target than on the source.
A boot repair will read the C: ID partition and correct it on the boot manger.



After you cloned the HDD
1) EFI - 100M Fat32
2) Reserved - 16M raw
3) C: - NTFS
4) Recovery - 800M NTFS
partitions on the SSD, detach the HDD (SATA or power cable).
Boot from the SSD, open Macrium Reflect and choose to fix the boot loader. It will read the C: ID partition and correct it on the boot manger.

If you still have the SSD that now doesn't boot, you can try to rebuild the EFI partition.
I can give you the instructions.

FIXED!

I did everything you said here, in the order you said to do it, and the problem is fixed!

It boots into the SSD C Drive with or without the Data D drive attached, and I rebooted a couple of times just to be certain.

I then restored the D Data drive, using Macrium, choosing the options to delete the target partitions first.

Rebooted and few times, and everything works OK

Thank you your help Megahertz, thanks to others for their advice too.

Good to know you have it fixed.