What's causing W10 to not boot when CSM is disabled?

[lafrente]

It's stuck in BIOS logo. Partition is GPT.

[Whatisthis]

You’ll have to do a repair install. It doesn’t have the uefi boot loader if windows was installed with csm enabled.

[lafrente]

1 minute ago, Whatisthis said:

You’ll have to do a repair install. It doesn’t have the uefi boot loader if windows was installed with csm enabled.

Luckily it still booted when I re-enabled CSM and I realized that it wasn't worth the risk. I'll just keep it as is.

[Whatisthis]

Just now, lafrente said:

Luckily it still booted when I re-enabled CSM and I realized that it wasn't worth the risk. I'll just keep it as is.

Yeah, basically the issue is that the thing that tells the system where the os is installed for a UEFI system is not there. 
 

If you don’t care about a few security things (secure boot, TPM, etc.) you can leave good enough alone.

[lafrente]

6 minutes ago, Whatisthis said:

Yeah, basically the issue is that the thing that tells the system where the os is installed for a UEFI system is not there. 
 

If you don’t care about a few security things (secure boot, TPM, etc.) you can leave good enough alone.

Maybe I try it again after I get a recent backup of the full system. The slightest possibility of having to reinstall Windows and losing all my configurations is enough to scrap the idea.

[Whatisthis]

30 minutes ago, lafrente said:

Maybe I try it again after I get a recent backup of the full system. The slightest possibility of having to reinstall Windows and losing all my configurations is enough to scrap the idea.

Hold on…go to bios. Go to where you can select the boot device. Do you have a UEFI device there? If so, make it the first boot device and turn csm off. If not, see if you can add the uefi disk.

 

might be a simple bios issue.