I want to switch from MBR (BIOS) to GPT (UEFI)

open a command prompt (admin) and run:
mbr2gpt /validate

That will tell you if that command will convert your drive to GPT or not.

This is what I can guarantee. If you are successful in converting your SSD to GPT and booting in UEFI mode, you will notice absolutely NO difference whatsoever in performance.

If you run the above command and see:

Code:

C:\WINDOWS\system32>mbr2gpt /validate
ERROR: MBR2GPT can only be used from the Windows Preinstallation Environment. Use /allowFullOS to override.

hold down the shift key while clicking power > restart > click troubleshoot > click command prompt

type: mbr2gpt /validate

or

type: mbr2gpt /validate /allowfullos


On the computer that the command was tested it displayed:
attempting to validate disk 0
retrieving layout of disk
validating layout, disk sector size is: 512 bytes
disk layout validation failed for disk 0

Brink said:

Go ahead and post a screenshot showing the full layout in Disk Management just to be sure, but usually as long as you do not have more than 3 partitions on the disk, it should be fine.

https://i.imgur.com/ovSvbGn.png

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NavyLCDR said:

open a command prompt (admin) and run:
mbr2gpt /validate

That will tell you if that command will convert your drive to GPT or not.

This is what I can guarantee. If you are successful in converting your SSD to GPT and booting in UEFI mode, you will notice absolutely NO difference whatsoever in performance.

Validation completed successfully https://i.imgur.com/uIE1Uev.png

ashramnavivi said:

https://i.imgur.com/ovSvbGn.png
Validation completed successfully https://i.imgur.com/uIE1Uev.png

You can post those Imgur images so they appear directly in your post, like this....

[IMG]https://i.imgur.com/ovSvbGn.png[/IMG]

[IMG]https://i.imgur.com/uIE1Uev.png[/IMG]

...which looks like this.

Bree said:

You can post those Imgur images so they appear directly in your post, like this....

[IMG]https://i.imgur.com/ovSvbGn.png[/IMG]

[IMG]https://i.imgur.com/uIE1Uev.png[/IMG]

...which looks like this.

I know for that bbcode, used it in many other forums, but never actually tried doing so here, will do it in the future :P

ashramnavivi said:

I know for that bbcode, used it in many other forums, but never actually tried doing so here, will do it in the future :P

The easiest way to do it is to click the Insert Image icon in the editor.



Then choose 'From URL'.



But perhaps even easier it to use 'From Computer' and upload it directly, no need for Imgur at all.

Brink said:

@ashramnavivi,

You look good to go as far as your partition layout on your Windows disk.

I would recommend to temporarily disconnect your "D" drive until after the conversion has completed just to make sure nothing is done to the "D" drive by mistake.

Alright I will do that, just one more question, should I keep CSM support in my BIOS enabled after converting from MBR to GPT (UEFI)?

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Also, I will convert using my full Windows through the cmd (using /allowfullos), after the conversion is done, should I turn off my PC and boot it into BIOS and then set Storage Boot Option Control to UEFI Only?

Brink said:

CSM is for "Legacy BIOS", so you would want to have that disabled after switching to UEFI to avoid having your system not boot.

Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

Alright, and last question, how can I be 100% sure that my motherboard supports the UEFI?