Booting into Windows 10 Installer from Mac Pro (2012)

Question

I am trying to boot into the Windows 10 Installer (7 or 8 would work as well) on my 2012 Mac Pro using a USB drive. When holding the option key on startup, it recognizes the USB as bootable and lets me select it. When selected, the screen freezes for a minute before the Mac restarts and reverts to its other drive (Windows 7 and 8 fail the same way). Booting into other operating systems such as Ubuntu yield perfect results.

I have also tried reinstalling OS X to use BootCamp, but the keyboard shortcuts for recovery mode and other startup utilities do not work.

What is the best way to get Windows running on my Mac Pro?

Answer 1

Before the UEFI standard was adopted, there was EFI. This EFI standard is used by Apple to boot OS X and macOS. Many Linux distributions are also able to EFI boot. Being able to EFI boot a Ubuntu installer or live version does not automatically mean your Mac can UEFI boot a Windows installer.

The model identifier for you Mac is MacPro5,1. Information regarding Apple's requirements to install Windows can be found in the info.plist file contained within the Boot Camp Assistant. The excerpt shown below was taken from this file under macOS Catalina 10.15.7. This indicates your model Mac is not suppose to boot the Windows installer from a USB drive. Instead you are suppose to install Windows by booting from a DVD.

    <key>PreUSBBootSupportedModels</key>
    <array>
        <string>MacBook7,1</string>
        <string>MacBookAir3,2</string>
        <string>MacBookPro8,3</string>
        <string>MacPro5,1</string>
        <string>Macmini4,1</string>
        <string>iMac12,2</string>
    </array>

The next excerpt shows Apple does not support Windows 10 for your model Mac.

    <key>SupporedNonWin10Models</key>
    <array>
        <string>MacBook6,1</string>
        <string>MacBook7,1</string>
        <string>MacBookAir3,1</string>
        <string>MacBookAir3,2</string>
        <string>MacBookAir4,1</string>
        <string>MacBookAir4,2</string>
        <string>MacBookPro6,1</string>
        <string>MacBookPro6,2</string>
        <string>MacBookPro7,1</string>
        <string>MacBookPro8,1</string>
        <string>MacBookPro8,2</string>
        <string>MacBookPro8,3</string>
        <string>Macmini4,1</string>
        <string>Macmini5,1</string>
        <string>Macmini5,2</string>
        <string>Macmini5,3</string>
        <string>iMac10,1</string>
        <string>iMac11,1</string>
        <string>iMac11,2</string>
        <string>iMac11,3</string>
        <string>iMac12,1</string>
        <string>iMac12,2</string>
        <string>MacPro5,1</string>
    </array>

The next excerpt shows Apple does not support UEFI booting of Windows or the Windows installer for your model Mac. This means you should not select EFI Boot from the Mac Startup Manger when booting from the Windows installer.

    <key>PreUEFIModels</key>
    <array>
        <string>MacBook7</string>
        <string>MacBookAir5</string>
        <string>MacBookPro10</string>
        <string>MacPro5</string>
        <string>Macmini6</string>
        <string>iMac13</string>
    </array>

I should also point out that this info.plist file specifies Apple's requirements. You can not change these requirements for your Mac by editing this file.