MP 1,1-5,1 Mac Pro 3,1 - Windows 10 does not see OSX install

[r6mile]

Hi,

I have managed to install Windows 10 in my 2008 Mac Pro, using a burned DVD onto a completely separate hard drive. I then installed the Boot Camp Drivers that I prepared on my Mac Pro - I had to use Windows 7 compatibility mode for them to even launch. I understand these are older BootCamp drivers not designed for Windows 10, so this is probably the root of my issue.

Other than Win10, I have High Sierra in a AHCI blade SSD, and another hard drive with El Capitan and Snow Leopard partition. The Boot Camp startup manager can see the El Capitan and Snow Leopard installations, but not the High Sierra one in the blade SSD, which is obviously problematic as I have a GPU without boot screen (GTX 750Ti) as it's my main OSX.

Also, Windows explorer cannot see any of the HFS+ Mac drives - I have installed the HFS+ drivers for Windows 10 onto the System32/drivers folder following instructions in another thread.

Any idea how I can solve this problem? I am aware that all of this is obviously unsupported, but hopefully it's an easy fix?

 

[Ludacrisvp]

remove the drive that has windows running on it, then it should boot up into macos all on its own.
then consider getting a new GPU with a (UEFI) GOP enabled ROM to leverage OpenCore or @Dayo's refind variant to get boot screens without using a flashed GPU and have an arguably better time in macos and windows. Like an AMD RX 580 paired with @Syncretic's SSE4.2 emulator for macOS.

 

[r6mile]

remove the drive that has windows running on it, then it should boot up into macos all on its own.
then consider getting a new GPU with a (UEFI) GOP enabled ROM to leverage OpenCore or @Dayo's refind variant to get boot screens without using a flashed GPU and have an arguably better time in macos and windows. Like an AMD RX 580 paired with @Syncretic's SSE4.2 emulator for macOS.

Thank you, yes my fallback is to pull put the Windows drive, though I was hoping there was an easier software based fix for this as pulling out drives can be a bit of a pain.

Re a new GPU, yes I have considered it, but I barely use this Mac Pro so can't really justify spending the expense. Especially as a RX580 will be severely throttles in a che 3,1 anyway. Also, the GPU was a recent gift from my cousin, I would feel a bit awkward if he asked me how I'm getting on with it, to then say I've sold it

And re Opencore, I thought it didn't support legacy Windows installations?

 

[Dayo]

You can get a bootscreen by following THIS GUIDE which prefers Legacy Windows.

The process requires Fully Compatible GPUs (GOP or UGA Based Mac Pre-Boot Screen Support) or Semi Compatible GPUs with Valid GOP. It doesn't matter whether the GPU is Legacy (Pre GOP) or Current as long as it is one of the two types.

I doubt that the GTX 750Ti falls into either category though as most likely does not have the "Valid GOP" bit

You can install Windows by following THIS GUIDE.

The RX580 is most likely indeed throttled on a cMP 3.1 but some would dispute it being severely so.

 

[r6mile]

Thank you all, something to consider. The 750Ti is a tricky card as it needs Webdrivers too, but I like that it doesn't need extra power, and performance it's absolutely fine for me for now, so I need to assess my options carefully.

In the meantime though, any idea how I can fix my issue about not seeing the HFS+ drives and Boot Camp startup disk not seeing my High Sierra? Could the latter be because Windows sees a PCIe drive as external or something?

 

[Dayo]

In the meantime though, any idea how I can fix my issue about not seeing the HFS+ drives and Boot Camp startup disk not seeing my High Sierra? Could the latter be because Windows sees a PCIe drive as external or something?

Sorry, no idea on that front.