SN550 not being recognised (CSM issues)

Aodhan5000 · 01-09-2021 11:11AM #1

Hi all,

So I've an SN550 1TB drive in my PC as my boot drive. When I was installing windows on it when I was upgrading my build (around the start of the year roughly) I had to enable the compatibility support module for it to be recognised. Grand job worked away fine.

Now over the last few weeks when I turn on the computer it'll bring up that screen that you usually get before installing windows where it says something about inserting boot media and pressing any key.

I have to then hard shut it down, go into bios where the SN 550 is not showing up but the 2 SATA hard drives are coming up , turn off CSM, save and exit, go into bios again, enable CSM, save and exit and then go into bios again to see if the drive is being detected and usually it is. Then I'm good to go again.

There is a bunch of other settings under the CSM setting that I'm not really sure of. Will post a pic of it when I'm home. Something about UEFI Vs legacy for a few different settings and that I should follow manufacturers guidelines or something. Anyone have any words of wisdom? Motherboard is a B550 A gaming with a 3600.

Cuddlesworth · 02-09-2021 08:52AM

What version of Windows were you installing that would require CSM to be enabled?

Aodhan5000 · 02-09-2021 12:14PM

Just windows 10 pro. When I first booted up the PC and went into bios the SN550 wasn't turning up and I just saw something online about enabling CSM would probably make the drive show up. Or it might have been that the usb wasn't being detected, either or, I enabled CSM and I was good to go then

Spear · 02-09-2021 12:15PM

I wonder if the drive is still MBR, and not GPT. That could explain why CSM would be needed.

Aodhan5000 · 02-09-2021 04:55PM

Ya Spear you're right it's an MBR partition. Did I format it as an MBR drive or is it just something that windows does when installing onto a fresh SSD (the SN550 was brand spanking new)? I might have enabled CSM to detect the bootable USB, idk. So I've guessing I need CSM because that allows for BIOS to support MBR as UEFI doesn't support it.

Anyway when launching without CSM enabled it won't boot windows so I'm figured now that I've installed Windows with CSM enabled there's no going back.

IMG_20210902_175425.jpg

However when I boot (only as far as UEFI) with CSM disabled it always detects the drive. When CSM is enabled, the UEFI only detects the drive when I made a change to CSM settings on the previous UEFI boot.

I've included a picture of the CSM Configuration settings. When I set all to legacy she worked away fine for a few boots but back to square one after the 4th try which was after fully disconnecting her from AC. So is there any setting I can twiddle with or will I have to convert the drive from MBR to GPT. I have heard of a Windows 10 tool called MBR2GPT but if I'd rather avoid that hassle if I can? Thanks

EDIT: There's only 3 partitions on the drive so i think MBR2GPT is an option. Anyone any experience with it?

Spear · 02-09-2021 06:46PM

I've used mbr2gpt back some years ago, and it's a fairly safe and easy process. It's necessary for Windows 11, so might as well get it out of the way now.

Aodhan5000 · 02-09-2021 08:13PM

https://www.boards.ie/discussion/comment/117839403#Comment_117839403

Alrighty, I'll give it a go when I get a chance. Cheers for the help!

SN550 not being recognised (CSM issues)

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