Guide: Multibooting UEFI on Separate Drives

[jefftr66]

Good luck - the above worked for me but otherwise I'm not much help with Windows

 

[t33j4y]

Good luck - the above worked for me but otherwise I'm not much help with Windows

Well, it changed somewhat - now the installer tells me that the EFI partition is formatted as NTFS. What the hell, I just formatted it as fat32. And when I look at it using Diskpart - command "List Volume" it says it's FAT32...

I also moved the disk to SATA-0 afterwards, but this didn't make a difference.

I'm going to try creating the USB installer again, using Rufus instead. If that doesn't work, I'll reformat the drive using Disk Utility again. One thing at a time. This is really bothersome and I don't get why it's such a problem - it's a computer that has run Windows 10 before and with only the Barracuda installed, it is in all respects a standard PC with no Hackintosh stuff to "interfere"

 

[Going Bald]

Well, it changed somewhat - now the installer tells me that the EFI partition is formatted as NTFS. What the hell, I just formatted it as fat32. And when I look at it using Diskpart - command "List Volume" it says it's FAT32...

I also moved the disk to SATA-0 afterwards, but this didn't make a difference.

I'm going to try creating the USB installer again, using Rufus instead. If that doesn't work, I'll reformat the drive using Disk Utility again. One thing at a time. This is really bothersome and I don't get why it's such a problem - it's a computer that has run Windows 10 before and with only the Barracuda installed, it is in all respects a standard PC with no Hackintosh stuff to "interfere"

Before you wipe the USB, when you get to the install screen to select a volume to install, select the non-efi partition of the drive you formatted with disk utility and delete the partition first, then click Next and allow the installer to create and format the Windows partitions.

 

[t33j4y]

Before you wipe the USB, when you get to the install screen to select a volume to install, select the non-efi partition of the drive you formatted with disk utility and delete the partition first, then click Next and allow the installer to create and format the Windows partitions.

Thanks

I did however create another installer on a different USB drive. Didn't work, complained about FAT32 again.

I then followed the steps here to clean the Barracuda and prepare it. Disabled Legacy boot and booted from the Rufus-created USB. Cleaned the disk again in Diskpart, not creating the EFI. Then, in Partition overview I selected the empty disk and selected "New" and the Windows partitions were created. Then proceeded to copy files which actually worked this time.

But alas, when the computer rebooted, it just booted from the USB drive again. Removed that and rebooted and went to select bootdisk. It did not show up as UEFI. Only the MacOSX selection (the disk is not connected right now, so this is the BIOS listing)

Rebooted into BIOS, enabled Legacy mode, selected the Barracuda from the Legacy list. No filesystem found

I feel like the BIOS should be picking up the UEFI listing but isn't.

 

[t33j4y]

So, I have now tried with a different drive (no change), on a regular SATA 300 port (no change) and to install with Secure Boot enabled (no change)

I then proceeded to take the disk out and put in an external SATA enclosure and connect it to a Windows PC to investigate it in MiniTool Partition Wizard. And lo and behold - there is no EFI partition on it! Only the MSR and the main partition. I don't get that? But this would explain why the computer doesn't pick it up during boot. I just don't understand why the EFI partition is not installed.

I am tempted to wipe the BIOS and try again - but I am afraid what that will do the existing MacOS install UEFI listing I have, as this does work. Will the BIOS pick it up when I power on that drive again?

 

[Going Bald]

So, I have now tried with a different drive (no change), on a regular SATA 300 port (no change) and to install with Secure Boot enabled (no change)

I then proceeded to take the disk out and put in an external SATA enclosure and connect it to a Windows PC to investigate it in MiniTool Partition Wizard. And lo and behold - there is no EFI partition on it! Only the MSR and the main partition. I don't get that? But this would explain why the computer doesn't pick it up during boot. I just don't understand why the EFI partition is not installed.

I am tempted to wipe the BIOS and try again - but I am afraid what that will do the existing MacOS install UEFI listing I have, as this does work. Will the BIOS pick it up when I power on that drive again?

Your Rufus installed Legacy Mode. If using Rufus to create your USB you must select the UEFI option to create a UEFI installer. This is why I recommend the Microsoft USB creation tool - it enables both types of installation and automatically selects the UEFI on UEFI capable systems with CSM disabled.

 

[t33j4y]

Your Rufus installed Legacy Mode. If using Rufus to create your USB you must select the UEFI option to create a UEFI installer. This is why I recommend the Microsoft USB creation tool - it enables both types of installation and automatically selects the UEFI on UEFI capable systems with CSM disabled.

Thanks

I tried both Rufus (and with UEFI) and Microsoft installer. But I will go ahead and redo the USB drive first with Microsoft installer (I have no special preference for Rufus, it was an attempt to try something different as the Microsoft installer didn't seem to work.

Any opinion on the wiping BIOS part?

 

[t33j4y]

Ok...

I created a new Windows install USB drive using the Media Creation Tool.

1. Inserted USB drive in rear USB2.0 port
2. Booted computer (Legacy mode is off) and hit F12 to manually select USB drive
3. USB drive shows up as UEFI:Lexar 8GB
4. Selected this option - UEFI: Lexar 8GB as boot. It boots into Windows installer
5. I go through options, accepting license and so on. I do not put in windows license key. I ensure that the target disk is one big free unallocated space. I choose "Windows 10 Pro" as this is what I have a license for (for later)
6. I select "Next" and the installer does its thing, copying and setting up
7. When prompted to restart, I remove the USB drive.
8. Computer reboots and I get "No bootable devices found."
9. I reboot into BIOS and enable Legacy mode and reboot.
10. Computer reboots and I get "No bootable devices found."

I then boot into BIOS again and disable Legacy mode. Then I restart the Windows USB drive installer and hit Shift+F10 from the first screen to get a command prompt. In Diskpart, I select the target drive to see partitions.

Disk is GPT - but there is no EFI partition. (disk 1 is btw an NVMe drive, but doesn't show in volume overview b/c it's a MacOS Journaled, not recognizable)

 

[Going Bald]

Is your Mac OS drive connected? Check the Mac OS drive EFI/EFI for a Microsoft folder.
A Win10 UEFI installed drive should have a WinRe Tools partition, a Reserved partition, an EFI partition and a system partition.

 

[t33j4y]

Is your Mac OS drive connected? Check the Mac OS drive EFI/EFI for a Microsoft folder.
A Win10 UEFI installed drive should have a WinRe Tools partition, a Reserved partition, an EFI partition and a system partition.

MacOS Drive is not connected. Only the SSD intended for Win10 and then the NVMe drive (but computer doesn't support booting from NMVe)