Question Do I need to convert my C drive from MBR to GPT to instal an NVMe SSD?

laurencewithau

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Hi everyone. I have Windows 10 and an Asus Z97-AR motherboard. My C (OS) drive is a SATA SSD.
Recently I started a thread here about a problem with my new Crucial 1000 GB PCLe NVMe SSD. Reading back, it seems to me that I was more than a little confused, and I ended by stating, wrongly, that the new NVMe was faulty.
Just to clarify matters my present concern, given all that i have learnt since then, is to get the NVMe up and running at times 2, not the times 4 it is capable of, until such time as I can do a full system upgrade, which I know I can do thanks to all the help I was given by the contributors to that thread.
My present problem is that the NVMe in its M.2 port is not recognised by the PC despite the motherboard boot system being UEFI BIOS.
The reason, I have at last discovered, is that the C drive (OS) is MBR partition style, whereas it needs to be GPT for reasons of UEFI compatibility.
I hope I've got that right, otherwise I shall have to kill myself.
Getting it right is one thing; understanding it is another, and I don't.
So here are some questions.
Firstly, can I convert the MBR to GPT without having to wipe the C drive and the OS with it? It still is possible, by the way, and very easy, to download Windows 10 for free.
I have a 1TB hard drive that has plenty of free space for the C drive data, but I can't use the desktop PC without an OS, so would I be able to transfer it to the hard drive and use it.
Thirdly, do I need to ask whether the NVMe is MBR or GPT?
I should point out, too, that I intend to transfer the Windows 10 to the NVMe should it ever start earning its keep.
Thanks for reading this far.
Cheers, Laurence
 

androbourne

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Well firstly no. its not REQUIRED but it is recommended. If you stay with MBR then you cant use UEFI so your mobo has to run in legacy mode and you lose out on some mobo features.

Secondly yes you can convert MBR to GPT but then you have to remember to change it in your BIOS from legacy to UEFI or it wont boot. This also can be a crap shoot depending on the software you use and your mobo. Most of the time it will go through without problems however I have ran into issues in the past where sometimes it would convert to GPT and still fail to boot after changing the BIOS settings.

Normally I recommend for an OS drive to wipe/reload with GPT from the start so you dont run into any issues. Should be as simple as backing up your PC (if you need a free good backup program look into Veeam Agent) then format your C disk and reload Windows.
 
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laurencewithau

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Well firstly no. its not REQUIRED but it is recommended. If you stay with MBR then you cant use UEFI so your mobo has to run in legacy mode and you lose out on some mobo features.

Secondly yes you can convert MBR to GPT but then you have to remember to change it in your BIOS from legacy to UEFI or it wont boot. This also can be a crap shoot depending on the software you use and your mobo. Most of the time it will go through without problems however I have ran into issues in the past where sometimes it would convert to GPT and still fail to boot after changing the BIOS settings.

Normally I recommend for an OS drive to wipe/reload with GPT from the start so you dont run into any issues. Should be as simple as backing up your PC (if you need a free good backup program look into Veeam Agent) then format your C disk and reload Windows.
Hi androbourne. Thanks for your reply.
As I understand it, it's not just that "If you stay with MBR then you cant use UEFI so your mobo has to run in legacy mode and you lose out on some mobo features. " It's also that an NVMe SSD drive won't be recognised by the PC and won't work, because it needs UEFI.
Is that correct?
If not, then I'm back to square one when it comes to explaining why my NVMe is not recognised by the PC and is non-operational.
Thanks again.
Cheers, Laurence
 

laurencewithau

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Not correct.

For NVME drive to be recognized,
BIOS settings must be correct, drive recognized in BIOS,​
nvme controller drivers installed.​
Hi. Thanks for your reply. So bang goes the theory, but I'm not quite back to square one because you mention NVMe controller drivers, which I knew nothing about. I'll follow up that clue. Thanks again. Cheers, Laurence
 

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