Windows 10 BIOS mode on a 2009 Mac Pro

[s.m.t.]

Is it possible to install Windows 10 a 2009 Mac Pro in BIOS mode? I have it installed in EFI mode with GPT partitions. But I would like to use an MBR formatted disk to test a video driver issue.

 

[ActionableMango]

Yes several MP owners have done BIOS installations of Windows 10. In fact, there are a few examples where you have to do the BIOS installation, such as if you have a Mac Edition GTX680.

 

[s.m.t.]

do you use boot camp assistant? I have been booting from the USB key and installing from boot...

 

[ActionableMango]

No, I do not.

I vaguely remember when I used the USB drive and held ALT/OPTION at bootup that there were two separate icons, one for the BIOS installer and one for the EFI installer. But I could be wrong because (A) I never really paid much attention because I always wanted to do the EFI installer, and (B) I might be remembering the disc install instead.

What do you see for choices when you boot up? Just the EFI installer?

 

[s.m.t.]

I have a retail usb key installer... If I place that in and pull up the boot options, I only have a removable efi boot disk...

 

[ActionableMango]

Hmmm, according to this article you should see both:
https://msdn.microsoft.com/en-us/wi...desktop/boot-to-uefi-mode-or-legacy-bios-mode

It would be time consuming, but you could always install Windows 7 BIOS and then update to 10.

 

[s.m.t.]

Guessing the usb key Microsoft ships only has an EFI boot option. I popped in a Windows 7 cd and do have two options. Windows and efi boot. Sadly choosing Windows causes it to lock up (stuck on the boot loader).

 

[supermariofan25]

Try creating a Windows 10 USB by downloading the .iso file from Microsoft then using Bootcamp Assistant to make the install USB. This USB should be able to boot using legacy mode (Selecting 'Windows' instead of 'EFI Boot').

 

[s.m.t.]

Try creating a Windows 10 USB by downloading the .iso file from Microsoft then using Bootcamp Assistant to make the install USB. This USB should be able to boot using legacy mode (Selecting 'Windows' instead of 'EFI Boot').

Thanks, was not aware you could download an iso from Microsoft, will give that a try!

 

[s.m.t.]

Success! Had to download the Microsoft tool and pull down an ISO, burned that to DVD. At boot I have both boot options!

Thanks for the help all!