F5F Stay Refreshed Software Operating Systems Getting ready for a new update on Windows 11 because of Secure Boot and a CSM issue in your BIOS settings.

Getting ready for a new update on Windows 11 because of Secure Boot and a CSM issue in your BIOS settings.

Getting ready for a new update on Windows 11 because of Secure Boot and a CSM issue in your BIOS settings.

A
avi15
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167
03-30-2026, 06:15 AM
#1
Hi, I am trying to update to Windows 11 for the first time. I have all the right hardware, like my B660M Pro RS motherboard and an Intel Core i5-12400F processor. I did enable Secure Boot in my BIOS, but when I turn CSM off, my old Windows 10 hard drive no longer shows up on my computer. (I originally turned on CSM from my BIOS so that I could boot with my regular Windows 10 drive without any trouble - it worked fine back then, but this blocks the Windows 11 upgrade). My storage is a Kingston SSD with 480GB and uses the NTFS file system. If buying a new SSD isn't an option because of its size, is there another way? I really need help, so please let me know what to do next. Thanks!
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A
avi15
03-30-2026, 06:15 AM #1

Hi, I am trying to update to Windows 11 for the first time. I have all the right hardware, like my B660M Pro RS motherboard and an Intel Core i5-12400F processor. I did enable Secure Boot in my BIOS, but when I turn CSM off, my old Windows 10 hard drive no longer shows up on my computer. (I originally turned on CSM from my BIOS so that I could boot with my regular Windows 10 drive without any trouble - it worked fine back then, but this blocks the Windows 11 upgrade). My storage is a Kingston SSD with 480GB and uses the NTFS file system. If buying a new SSD isn't an option because of its size, is there another way? I really need help, so please let me know what to do next. Thanks!

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A
AliMuhammed
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50
04-03-2026, 03:46 AM
#2
Sure, please share a picture of the Disk Management screen. You need to upload it here and give us the link. Moving from CSM back to UEFI needs you to split your drive's partitions and change them from MBR format to GPT format. To do this, use the mbr2gpt tool.
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A
AliMuhammed
04-03-2026, 03:46 AM #2

Sure, please share a picture of the Disk Management screen. You need to upload it here and give us the link. Moving from CSM back to UEFI needs you to split your drive's partitions and change them from MBR format to GPT format. To do this, use the mbr2gpt tool.

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BRiiNKS
Junior Member
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04-03-2026, 06:58 AM
#3
It looks like that happens because I found out our main drive was NTFS while the other one was just regular data. Is there an issue with how we made these partitions? Thanks, I just followed normal steps when setting up Windows 10.
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BRiiNKS
04-03-2026, 06:58 AM #3

It looks like that happens because I found out our main drive was NTFS while the other one was just regular data. Is there an issue with how we made these partitions? Thanks, I just followed normal steps when setting up Windows 10.

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FureaMC
Senior Member
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564
04-03-2026, 09:59 AM
#4
What is that 32GB drive? Is it a USB flash drive? It has an UEFI bootloader. Either take the drive out or delete the 99MB EFI system partition from it. These commands will remove the EFI system partition from your 32GB drive. diskpart list disk select disk 1 list partition select partition x (pick number two or three for the EFI system partition) delete partition override To turn your OS drive into a UEFI ready one, do this: Run a check from an elevated command prompt. Type mbr2gpt.exe /validate /disk:0 /allowFullOS If that works fine, then run the conversion. Type mbr2gpt.exe /validate /disk:0 /allowFullOS Then go into BIOS and turn off CSM, set the first boot device to Windows Boot Manager.
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F
FureaMC
04-03-2026, 09:59 AM #4

What is that 32GB drive? Is it a USB flash drive? It has an UEFI bootloader. Either take the drive out or delete the 99MB EFI system partition from it. These commands will remove the EFI system partition from your 32GB drive. diskpart list disk select disk 1 list partition select partition x (pick number two or three for the EFI system partition) delete partition override To turn your OS drive into a UEFI ready one, do this: Run a check from an elevated command prompt. Type mbr2gpt.exe /validate /disk:0 /allowFullOS If that works fine, then run the conversion. Type mbr2gpt.exe /validate /disk:0 /allowFullOS Then go into BIOS and turn off CSM, set the first boot device to Windows Boot Manager.

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