Question Can't boot Windows with CSM turned off even boot drive is GPT.

[alexander_benjamin]

FYI I've been struggling with this for over 2 years lol, here's what I did:
- convert from MBR to GPT
- went back from W11 to W10
- absolutely watched hundreds of youtube video
- tried disconnecting HDD to make SSD works
PC info:
- BIOS mode is Legacy (I can't change to UEFI, since booting in CSM is impossible)
- Secure Boot State is unsupported (motherboard DOES support, SSD is GPT and my GPU is UEFI compatible)
Pleaseee help me, I wanted to game BF6 so bad. And a lot of things too not BF6 only

 

[Misgar]

I'd start from scratch and install a fresh copy of Windows on another drive (SSD) and experiment to see what's possible.

Stick with Windows 10, or create a "special" USB key using Rufus to tweak Windows 11 so you don't need Secure Boot, TPM 2.0, a modern CPU (2018+) and 4GB RAM.
https://windowsforum.com/threads/ho...restrictions-and-create-local-account.348702/

I have a number of old PCs (going back to 2010) which boot into Windows 10.

Most have small SATA SSDs (120GB/240GB) with the disks formatted MBR and the BIOS set to CSM/Legacy.

Others have the drive formatted GPT and the BIOS set to UEFI.
https://cpuforever.com/resources/csm-vs-uefi/

BIOS mode is Legacy (I can't change to UEFI, since booting in CSM is impossible)

I believe (and I may be wrong) that Legacy (aka CSM) requires the drive to be formatted MBR. If the BIOS is set to UEFI-only (no Legacy/CSM enabled) then I'd expect the disk to be formatted GPT.

By converting your drive from MBR to GPT, but not being able to set UEFI, might account for your drive no longer booting into Windows.

If your boot drive is 2TB or smaller, you don't "need" GPT.

MBR has its limitations (only 4 primary partitions), but it's adequate for booting old systems from drives less than 2TB.

If there's anything important on your current boot drive that isn't backed up, put the drive to one side and experiment with a cheap SATA SSD. Even 120GB is enough to install Windows and play around with BIOS settings.

Disconnect all your drives apart from the SSD you intend to install Windows on. Good luck.

Alternatively, I'm sure someone could provide diskpart commands to create a UEFI boot partition on your drive, but this can be tricky if you're not 100% confident. We'd need a map of your drive partitions extracted from Windows Disk Management.

 

[alexander_benjamin]

I'd start from scratch and install a fresh copy of Windows on another drive (SSD) and experiment to see what's possible.

Unfortunately that's what I did, maybe both of them were all MBR and not originally GPT (the pc was purchased about 5 years ago) and yes, I also formatted into GPT back then.

I believe (and I may be wrong) that Legacy (aka CSM) requires the drive to be formatted MBR. If the BIOS is set to UEFI-only (no Legacy/CSM enabled) then I'd expect the disk to be formatted GPT.

My motherboard is default by Legacy, there's two options to choose which is Legacy and UEFI. I might be dumb but I used EaseUS to actually converted the drive, however it all works well within Legacy as if drive is also GPT.

If there's anything important on your current boot drive that isn't backed up, put the drive to one side and experiment with a cheap SATA SSD. Even 120GB is enough to install Windows and play around with BIOS settings.

This is what I did today lol, I updated my BIOS version and smart enough to play around with my 2 worthy SDD which is what I'm using, Rufus it all and completely underestimated Windows for doubting I can bypass this.

Alternatively, I'm sure someone could provide diskpart commands to create a UEFI boot partition on your drive, but this can be tricky if you're not 100% confident. We'd need a map of your drive partitions extracted from Windows Disk Management.

I will reply with a new link to my map. It should be full.

 

[alexander_benjamin]

 

[SkyNetRising]

Bootloader is located on 1TB drive (System, Active, 3GB partition).
That is MBR drive and can boot onto legacy mode only.

You have 111GB drive converted to GPT (drive containing OS partition).
It doesn't contain bootloader. You can not boot from it.
Therefore your system can not boot into UEFI currently.

You'd have to create UEFI bootloader on 111GB drive. Then you'd be able to boot from it in UEFI mode.

 

[alexander_benjamin]

Bootloader is located on 1TB drive (System, Active, 3GB partition).
That is MBR drive and can boot onto legacy mode only.

You have 111GB drive converted to GPT (drive containing OS partition).
It doesn't contain bootloader. You can not boot from it.
Therefore your system can not boot into UEFI currently.

You'd have to create UEFI bootloader on 111GB drive. Then you'd be able to boot from it in UEFI mode.

Oh my god, really? Holy moly I wasn't thinking about that. I thought which drive has Windows folder is the one that boots. Is there any video to fix this?