Fresh install - no UEFI boot option.

[Steelbom]

So I've got two SSDs in my system - 250GB and 500GB. Previously the 250GB was a boot drive and the 500GB storage for games. I've switched it around, 250GB is now for games and my OS is on the 500GB.

But it's not booting for some reason. In the BIOS it doesn't show up in the boot manager as a UEFI bootable device, but my 250GB model did.

Whilst I was transferring, I had both the 250GB and 500GB with OS installed and was booting via UEFI to the 250GB model which let me choose to boot the OS on either drive.

So... not sure why my fresh installation doesn't have any UEFI bootable option... anyone have any idea?

 

[Tweak155]

Is this Windows 7 I'm guessing? Windows 10 handled it better when I switched to that.

What may be easier is to disconnect the 250gb during boot and see if the options change... then configure the BIOS and reconnect the 250gb.

 

[Steelbom]

Is this Windows 7 I'm guessing? Windows 10 handled it better when I switched to that.

What may be easier is to disconnect the 250gb during boot and see if the options change... then configure the BIOS and reconnect the 250gb.

Nah Windows 10. I've done a bunch of Googling and it seems when you install a new OS and there is already another drive with an EFI partition, Windows puts the boot files onto that other drive's partition....

So I need to re-create an EFI/MSR partition on my drive. Gunna skip the Windows recovery partition though, cuz I don't think I need that.

Currently doing a full backup... just in case. Then going to shrink my OS partition, create the EFI & MSR partitions and run bcdboot and hope for the best.

EDIT: I'm currently booted from a MBR USB external SSD. I plan on doing the above from this drive, though some people recommended using the installation media (USB thumb drive)... does it matter at all?

 

[Tweak155]

Nah Windows 10. I've done a bunch of Googling and it seems when you install a new OS and there is already another drive with an EFI partition, Windows puts the boot files onto that other drive's partition....

So I need to re-create an EFI/MSR partition on my drive. Gunna skip the Windows recovery partition though, cuz I don't think I need that.

Currently doing a full backup... just in case. Then going to shrink my OS partition, create the EFI & MSR partitions and run bcdboot and hope for the best.

EDIT: I'm currently booted from a MBR USB external SSD. I plan on doing the above from this drive, though some people recommended using the installation media (USB thumb drive)... does it matter at all?

I can't imagine one makes a difference over the other, although for the record I've never had a problem like what you're describing and I've always used the USB thumb drive for W10 installs. I typically leave the other drive with the OS already on it disconnected during the new drive install though in situations like this due to past headaches

Then once I'm back up, if I need to, I'll reconnect the original boot drive to copy files from it.

 

[Steelbom]

I can't imagine one makes a difference over the other, although for the record I've never had a problem like what you're describing and I've always used the USB thumb drive for W10 installs. I typically leave the other drive with the OS already on it disconnected during the new drive install though in situations like this due to past headaches

Then once I'm back up, if I need to, I'll reconnect the original boot drive to copy files from it.

Yep, that's the way to go. I could have easily done this, or even just copied over or deleted the EFI partition on the other drive so it would make the new one but yeah, didn't know.

Hopefully creating an EFI partition is as simple as it sounds.

EDIT: Success. For anyone who falls into this situation in the future this is what I did:

Booted into external SSD which I use for testing.

Used AOMEI partition assistant (free version) to resize my OS drive (500MB before the volume, not after).

I then followed the steps here: https://www.disk-partition.com/windows-10/missing-efi-partition-windows-10.html

NOTE: method 2 and I started from step 3 (creating EFI partition).

Created EFI and MSR partitions as instructed.

Then ran bcdboot for my OS drive and specified UEFI only. Default instructions are for both BIOS and UEFI.

bcdboot E:\Windows /s E: /f UEFI

The above line is what I used, and my OS drive is letter "E". YMMV, good luck.

Glad I got it sorted out without any headaches lol.