Solved MBR to GPT

jaylob4 · Nov 3, 2024

Apologies if this is in the wrong forum.

To reduce typing questions

If any reader has read my recent thread, Here I have rebuilt my PC with a new MB but re-installed the same SSD with my existing Win 10 Pro OS, the intention soon is to upgrade to Win11.

Before replacing the old MB I cloned my existing SSD just in case of issues.

Both my existing OS SSD and the SSD I used for the clone are MBR configurations, both have the same GB capacity.

I need to convert my existing SSD that contains the OS from MBR to GPT to enable both UEFI and TPM 2 that my new MB supports.

Because the clone is a mirror copy of my existing OS SSD and was cloned just before I replaced the old MB with a new MB and its new BIOS, If I convert OS SSD to GPT can I rely on the clone SSD, (MBR ) to get me out of trouble should I need to use it?

siliconbeaver · Nov 3, 2024

no matter.

Window 10/11 OS works no matter GPT or MBR disk.
Windows 7 wouldn't work this way.

jaylob4 · Nov 3, 2024

siliconbeaver said:
no matter.

Window 10/11 OS works no matter GPT or MBR disk.
Windows 7 wouldn't work this way.

Thank you but not answering the question I asked.

siliconbeaver · Nov 3, 2024

Windows 10/11. its image recovery ability is strong.
hence most users don't experience the problem. Its image can be universal. to install anywhere requests a Windows OS.
no matter GPT MBR TPM2 , , ,

bobkn · Nov 3, 2024

jaylob4 said:
Apologies if this is in the wrong forum.

To reduce typing questions

If any reader has read my recent thread, Here I have rebuilt my PC with a new MB but re-installed the same SSD with my existing Win 10 Pro OS, the intention soon is to upgrade to Win11.

Before replacing the old MB I cloned my existing SSD just in case of issues.

Both my existing OS SSD and the SSD I used for the clone are MBR configurations, both have the same GB capacity.

I need to convert my existing SSD that contains the OS from MBR to GPT to enable both UEFI and TPM 2 that my new MB supports.

Because the clone is a mirror copy of my existing OS SSD and was cloned just before I replaced the old MB with a new MB and its new BIOS, If I convert OS SSD to GPT can I rely on the clone SSD, (MBR ) to get me out of trouble should I need to use it?

Sure.

But I'd prefer to have an image of the boot drive, with the option to restore from the image if anything goes wrong.

I'd want such an image for PC hygiene, anyway.

Bree · Nov 3, 2024

jaylob4 said:
I need to convert my existing SSD that contains the OS from MBR to GPT to enable both UEFI and TPM 2 that my new MB supports.

Because the clone is a mirror copy of my existing OS SSD and was cloned just before I replaced the MB with a new one, If I convert OS SSD to GPT can I rely on the clone SSD, (MBR ) to get me out of trouble should I need to use it?

Rather than a cloned disk I rely on a Macrium Reflect system image to get me out of trouble should I need it (as occasionally I have). Other imaging software is available, such as Hasleo Free.

A system image has several advantages over a clone. For a start, it's smaller as it will only contain the used data from the partitions, and can be smaller still because it can use compression (typically 50%-70% of the size of the used data). This means you can hold multiple system images on one external drive, perhaps keeping previous versions, whereas for a clone its a single copy on a drive the same size as the original.

siliconbeaver said:
no matter.

Window 10/11 OS works no matter GPT or MBR disk.

jaylob4 said:
Thank you but not answering the question I asked.

Actually, it did. You should still be able to boot the MBR clone should you ever want to.

Ghot · Nov 3, 2024

@jaylob4

You're building a new computer, and going to eventually run Win 11.

1. Make a backup of the Win 10 you're running now.
2. Convert all your disks to GPT

Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

How to Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

www.tenforums.com

3. Do a clean install of Win 11.

Clean Install Windows 11

This tutorial will show you step by step on how to clean install Windows 11 at boot on your PC with or without an Internet connection and setup with a local account or Microsoft account. Windows 11 has all the power and security of Windows 10 with a redesigned and refreshed look. It also comes...

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Bree · Nov 3, 2024

Ghot said:
@jaylob4

You're building a new computer, and going to eventually run Win 11.

1. Make a backup of the Win 10 you're running now.
2. Convert all your disks to GPT

3. Do a clean install of Win 11.

I have successfully converted several machines from MBR to GPT. The method I used was to first make a system image of the old MBR system. Then I clean installed the same version of Windows in UEFI/GPT mode. Next I restored JUST the C: partition from the system image, to replace the one created by the clean install. The final step was to use the 'fix Windows boot problems' tool from a Macrium Reflect bootable rescue usb to create the correct boot entry.

jaylob4 · Nov 3, 2024

bobkn said:
Sure.

But I'd prefer to have an image of the boot drive, with the option to restore from the image if anything goes wrong.

I'd want such an image for PC hygiene, anyway.

I understand and while a clone can be useful an image/s of the OS is a better method and one I will adopt from now on in once Win 11 is installed, up and running.

SIW2 · Nov 3, 2024

You can convert it to gpt now. You could try microsoft mbr2gpt.exe first.

I usually do it manually but mbr2gpt is easier for people not familiar with the process.

the manual method:

1. use something to non destructively convert the disk to gpt ( e.g. free version of diskgenius)

rt click the mbr disk, from the context menu select convert to gpt, then click Save All

The disk is now gpt and all the partitions and everything on them is still there. But it wont boot until an esp partition with the required files has been created, It is very easy to do

2. Create an esp partition on the disk ( if there is the old 100mb system partition can delete that and use the space to create the esp)

3. populate the esp partition using bcdboot command.

takes less than a minute.

Winuser · Nov 3, 2024

SIW2 said:
You can convert it to gpt now. You could try microsoft mbr2gpt.exe first.

I usually do it manually but mbr2gpt is easier for people not familiar with the process.

the manual method:

1. use something to non destructively convert the disk to gpt ( e.g. free version of diskgenius)

The disk is now gpt and all the partitions and everything on them is still there. But it wont boot until an esp partition with the required files has been created, It is very easy to do

2. Create an esp partition on the disk ( if there is the old 100mb system partition can delete that and use the space to create the esp)

3. populate the esp partition using bcdboot command.

takes less than a minute.

I wonder if @jaylob4 understands what you posted or if it's all computerese.

SIW2 · Nov 3, 2024

The OP is not dumb.

bobkn · Nov 3, 2024

SIW2 said:
The OP is not dumb.

Dumb, no.

Conversant? Maybe.

I guess I've never installed Win 10 or 11 on an MBR disk. AN MBR disk lacks the 100GB EFI Boot partition? That would make the conversion a bit more awkward.

jaylob4 · Nov 3, 2024

siliconbeaver said:
Windows 10/11. its image recovery ability is strong.
hence most users don't experience the problem. Its image can be universal. to install anywhere requests a Windows OS.
no matter GPT MBR TPM2 , , ,

My apologies @siliconbeaver, you answered my question.

jaylob4 · Nov 3, 2024

I'm not dumb but am not conversant with many things OS related.

What many here would consider a brisk walk in the park with such things is a slow one for me but I'll get there.

Right now my head is spinning, time for me to back off for a little while and digest.

SIW2 · Nov 3, 2024

If I can find an old mbr disk somehwhere I might post pics.

Like everything else, it is bleeding obvious once you have done. But not necessarily obvious before you have done it.

I have done it countless times. I figured it out by looking at the context menus and giving it a try.

SIW2 · Nov 3, 2024

rt click the mbr disk and select convert to guid partition table

click Save All

confirm

SIW2 · Nov 3, 2024

The disk is now gpt partition style . Might take a few seconds to do the conversion on an old mechanical disk.

To make space for esp partition, delete the old 100mb system partition

SIW2 · Nov 3, 2024

Next create the esp using the 100mb space

there is only 100mb space in this example so type in 100 mb and untick Create MSR which is not absolutely necessary

SIW2 · Nov 3, 2024

assign letters to the windows partition and the esp partition.

In this example I assigned G and Z

then populate the esp partition using bcdboot command

bcdboot [source windows directory] /s [target esp partition]

bcdboot g:\windows /s z:

or you could use the /f switch if you are running in a different mode

bcdboot g:\windows /s z: /f uefi

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