Updating to Windows 11 (Secure Boot, CSM problem BIOS)

[chris123austin]

Hi - I am trying to update to Windows 11 (finally) - I have all the right hardware I believe - B660M Pro RS, intel Core i5-12400F, etc.

I need to enable Secure Boot, which I have done - but then I am still in CSM, but when I disable CSM then my windows (Windows 10 install) hard drive is no longer being detected for some reason.

(I originally enabled CSM from my BIOS so I could boot up regularly with my old Windows 10 hard drive - which worked fine - but like I say, this doesn't allow me to upgrade to Windows 11).

My drive is Kingston SSD 480GB - File System NTFS

If the solution comes down to buying a new SSD then it's not a massive issue as I could do with a bigger one anyway - but if there is a quicker solution that would be preferable

Can somebody please help?
Regards

 

[SkyNetRising]

Please show screenshot from DIsk Management.
(upload to imgur.com and post link)

Going from CSM system to UEFI requires drive partitioning to be changed from MBR to GPT.
This can be done with mbr2gpt tool.

 

[chris123austin]

Please show screenshot from DIsk Management.
(upload to imgur.com and post link)

Going from CSM system to UEFI requires drive partitioning to be changed from MBR to GPT.
This can be done with mbr2gpt tool.

As I believe this shows, my C drive is NTFS. The 32 GB one is just a basic data drive. Thanks

So it's a problem with the partitioning? Thanks (I just set this up normally with Windows 10 install)

 

[SkyNetRising]

What is that 32GB drive? Some USB flash drive?
It contains UEFI bootloader. Either remove the drive or delete 99MB EFI system partition from it.
These commands will delete EFI system partition from 32GB drive.

diskpart​

list disk​

select disk 1​

list partition​

select partition x​

(select 99MB EFI system partition, x=2 or x=3)​

delete partition override​

To convert your OS drive to UEFI compatible, do following:

Run validation check (from elevated command prompt).

mbr2gpt.exe /validate /disk:0 /allowFullOS​

If validation is successful, then run conversion.

mbr2gpt.exe /validate /disk:0 /allowFullOS​

​

Then boot into BIOS,
disable CSM,
set first boot device to Windows Boot Manager.

 

[chris123austin]

What is that 32GB drive? Some USB flash drive?
It contains UEFI bootloader. Either remove the drive or delete 99MB EFI system partition from it.
These commands will delete EFI system partition from 32GB drive.

diskpart​

list disk​

select disk 1​

list partition​

select partition x​

(select 99MB EFI system partition, x=2 or x=3)​

delete partition override​

To convert your OS drive to UEFI compatible, do following:

Run validation check (from elevated command prompt).

mbr2gpt.exe /validate /disk:0 /allowFullOS​

If validation is successful, then run conversion.

mbr2gpt.exe /validate /disk:0 /allowFullOS​

​

Then boot into BIOS,
disable CSM,
set first boot device to Windows Boot Manager.

The 32 GB one is just a 'data' one with some regular photos , etc. on it. Kind of pointless but why not, I believe I disabled it in the boot up section of 'BIOS'

I'm watching the video on MBR now and my C drive is MBR like you said,

Yeah that's really weird about the bootloader thing, it always used to try and start up Windows from there and I never really gave it too much thought so just disable it at Boot,

I don't think it will cause a problem for the time being but yes that sounds like good advice.

I think I need to do the MBR thing first right? That's the main thing.

Update:: Okay I've deleted that according to your very clear and excellent instructions - Thanks! (I think it must have somehow been left over from when using that drive as a Windows installation media or something)

 

[SkyNetRising]

I think I need to do the MBR thing first right? That's the main thing.

First get rid of EFI system partition on 32GB drive.
Multiple EFI system partitions in same system can cause confusion.

You may also want to have windows install USB flash drive prepared.
Either windows 10 or windows 11.

 

[chris123austin]

First get rid of EFI system partition on 32GB drive.
Multiple EFI system partitions in same system can cause confusion.

You may also want to have windows install USB flash drive prepared.
Either windows 10 or windows 11.

Yep I've removed that now -

I still can't change from MBR on Disk 0 though, both of the commands executed successfully but I'm still seeing MBR in Disk Management

Oh I ran validation twice - because I was blindly reading (and you made a mistake there)

 

[chris123austin]

Okay - this time it worked.
I'm all booted up running as normal in UEFI mode - no longer CSM/legacy,
And my PC Health Check is telling me all is cool and I can move on to Windows 11.
So that's absolutely wonderful! What fantastic help you have been, and what clear and brilliant instructions you have given (note see above if you want to make the edit to /convert).

Thank you so much!

I really don't know how to thank you! You are a genius that's for sure!