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Installing High Sierra on a machine that already has Windows on another drive

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Hi guys,

I'm considering installing High Sierra to its own SSD on my machine, however at the moment I have Windows installed on its own SSD

I will primarily be using Windows on this machine for gaming, but just want MacOS to be able to run Logic.

One of the members on here in another thread mentioned I should install Windows after the Hackintosh install. I was curious how necessary this is? What are the potential negative implications if I install MacOS and leave my Windows install as is? Is it possible?

Like I say I'm more worried about my Windows install than the Mac

I have seen GoingBalds guide and will be using that when I do go to install, was just curious as to the importance of the order of the install

Any help appreciated :)
 

Going Bald

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When using separate drives order of installation is irrelevant.
 
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OK so just to clarify, if I was to load a fresh install of High Sierra onto a separate drive, it shouldn't affect the performance of my already installed Windows setup?

I noticed the member who mentioned this to me said something about changing the BIOS settings for the OSX install, and apparently the Windows install would then 'bend' round the BIOS changes?

Also I noticed in your guide that you mentioned setting up a EFI partition using the OSX setup USB pen, then deleting the OSX partition and leaving the EFI. Obviously the EFI bit wouldn't be present if I were to just install OSX now whilst leaving Windows as is. Would this be an issue? Or would it just mean going into the BIOS each time to change the order of my startup disks? (which I don't mind at all)

Sorry for all the questions, I'm just mega paranoid about messing up my well oiled Windows setup
 

Jamesbond007

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Before you attempt to install MacOS, disable or disconnect any Windows drives present to prevent the MacOS installation program messing with the Windows drives.
 

Going Bald

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Before you attempt to install MacOS, disable or disconnect any Windows drives present to prevent the MacOS installation program messing with the Windows drives.
Mac OS installation will not affect the Windows drive or any other unless directed by you via Disk Utility. The only reason to disconnect other drives is to prevent you from accidentally erasing/formatting the wrong drive.
 

Going Bald

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OK so just to clarify, if I was to load a fresh install of High Sierra onto a separate drive, it shouldn't affect the performance of my already installed Windows setup?

I noticed the member who mentioned this to me said something about changing the BIOS settings for the OSX install, and apparently the Windows install would then 'bend' round the BIOS changes?

Also I noticed in your guide that you mentioned setting up a EFI partition using the OSX setup USB pen, then deleting the OSX partition and leaving the EFI. Obviously the EFI bit wouldn't be present if I were to just install OSX now whilst leaving Windows as is. Would this be an issue? Or would it just mean going into the BIOS each time to change the order of my startup disks? (which I don't mind at all)

Sorry for all the questions, I'm just mega paranoid about messing up my well oiled Windows setup
No, installing HS on a separate drive will have no effect on the performance of the Windows drive.
Changes to the BIOS to allow installation of Mac OS have little or no effect on the operation of Windows.

EFI creation and deleting the partition is for installing Windows. This was to get an easy method to get an EFI partition as the first partition on the Windows drive because Clover did not react well to the EFI being the 3rd partition on the drive instead of the first. With Open Core and newer versions of Clover this is no longer an issue.
No need to change the BIOS startup drive each time. If you look at your manual you will find there is a function key you can hit on boot to allow you to select the boot device you want to use. Or, just make the Mac drive first in BBS boot order and select Windows or Mac OS at the boot select screen.
 
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Thank you both for your replies, really appreciate it. Gonna hold my breath and give it a go :)
 

Jamesbond007

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Mac OS installation will not affect the Windows drive or any other unless directed by you via Disk Utility. The only reason to disconnect other drives is to prevent you from accidentally erasing/formatting the wrong drive.
Are you certain about that? If this is true then it is one less worry.

However, if I were to setup such a dual boot system (not that I want to do that), I would still disable or disconnect other drives just to be on the safe side.

And how about installing updates afterwards? I am aware that installing Windows updates (especially Windows 10) may affect other drives, how about MacOS updates in this regard?
 
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I wish I listened to your advice to disable the drives. High Sierra install failed as the installer was corrupted, and it bricked the EFI thing on my Windows drive that makes it boot, so I couldn't boot into Windows anymore. Windows installer couldn't repair it either so I had to format and re-install everything to be able to use my machine.

Just gonna forget all about OSX and use Cubase I think hah.
 

Going Bald

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Are you certain about that? If this is true then it is one less worry.

However, if I were to setup such a dual boot system (not that I want to do that), I would still disable or disconnect other drives just to be on the safe side.

And how about installing updates afterwards? I am aware that installing Windows updates (especially Windows 10) may affect other drives, how about MacOS updates in this regard?
If you make sure to install the Win10 drive in the default slot (first slot the system looks at on boot) and make sure that you change the BBS boot order to Win10 drive first when doing Windows updates the updates will not affect the other drives. Once the update process comes back and says no updates are available, then you can reboot to BIOS and reset the boot order back to Mac OS drive first.
One way to make sure of this is to install 2 drives. When you reach the point in the Win10 installation to choose a drive for the install, choose the first one offered. Then, after installation, remove one drive and determine the default slot.
 
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