Guide: Multibooting UEFI on Separate Drives

[Going Bald]

I am trying to multiboot windows 10 and HS on SEPARATE Drives. High Sierra should be on SSD, win 10 should be on HDD. Currently, my High Sierra is on HDD.

I don't know if a want a win10 UEFI mode or if my system is UEFI. I followed @trs96 High Sierra Guide and installed HS on my HDD. Now i want to dual boot on separate drives

If i follow your words in the above post, It will install Win 10 on SSD and my High Sierra will remain on HDD. Am i correct ?

Thanks for the reply, I have hackintoshed only once so please bear with me.

Since you have a UEFI system, I recommend you install Win10 UEFI. It will boot and run faster than if you installed it Legacy Mode.

Yes, that is correct. You can use any Mac friendly cloning app to clone your HDD to the SSD if you want to swap drives - Win10 on HDD and Mac OS on SSD (CarbonCopyCloner and SuperDuper are 2 of them). Note that if you use the free copy, once cloned you will need to install Clover to the SSD and copy your config.plist from the HDD to the SSD along with any kexts or drivers you added when you first installed Clover - easiest to just replace the entire EFI folder in the EFI partition on the SSD with the one in the EFI partition on the HDD.

Once this is done and it boots from the SSD with the HDD disconnected, you can reconnect the HDD and reformat it as if you were going to install Mac OS on it. I would suggest selecting a 3 pass secure erase when you do the formatting of the HDD before installing Win10. This will write all zeros to the HDD sectors.

 

[AwaisFayyaz]

Thanks for the reply. Yes i want to swap the drives. so what i have to do is

Clone my HDD to SSD using CCC or SuperDoper
After cloning, replace the entire EFI folder in the EFI partition on SSD with the one in the EFI partition on the HDD.
One cloning is done and system boots from SSD with HDD disconnected, reconnect the HDD, format it and install windows according to your instructions.

1. That's it. i will be able to multiboot using the above steps?

2. What should be the Boot Mode? You said to set it to Legacy/UEFI when assuming that i am installing it on same drive.

3. While creating bootable USB for win 10. i should select these options ?

GPT Partition scheme for UEFI and FAT 32 File System

Thanks

 

[Going Bald]

Between Clone and after clone insert install Clover to SSD.
Create Windows USB following this guide:

https://support.microsoft.com/en-us/help/15088/windows-10-create-installation-media

note you must do this from a Windows machine

 

[jefftr66]

Trying to follow this guide to install Win 10 on a separate SSD - having trouble getting a bootable Win10 USB

I followed this guide to create the USB:

Tips: How to make Windows 10 install media on macOS High Sierra - macOS Discussions on AppleInsider Forums

Apple stripped the ability to make Windows 10 install media from a flash drive or external SSD in Sierra, but sometimes, you still need to be able to do it from a Microsoft-provided download.

forums.appleinsider.com

But when I boot into the boot screen it does not show as an option. Any ideas?

 

[jefftr66]

Trying to follow this guide to install Win 10 on a separate SSD - having trouble getting a bootable Win10 USB

I followed this guide to create the USB:

Tips: How to make Windows 10 install media on macOS High Sierra - macOS Discussions on AppleInsider Forums

Apple stripped the ability to make Windows 10 install media from a flash drive or external SSD in Sierra, but sometimes, you still need to be able to do it from a Microsoft-provided download.

forums.appleinsider.com

But when I boot into the boot screen it does not show as an option. Any ideas?

Ok I changed one thing in the above instructions - formatted the USB with GPT instead of MBR. Now it shows on the boot list but when I try to select it as the boot choice it just jumps back to the boot list screen.

 

[AwaisFayyaz]

Between Clone and after clone insert install Clover to SSD.
Create Windows USB following this guide:
https://support.microsoft.com/en-us/help/15088/windows-10-create-installation-media note you must do this from a Windows machine

Hi, i used free version of CCC to clone my HDD to SSD. After clone, i installed clover to SSD and copied EFI folder from EFI partition on my HDD to SSD. My High Sierra successfully booted from SSD.

Now, i wanted to install windows on HDD for dual boot. therefore i unplugged HDD sata cable and tried to boot from SSD Alone. But i was stuck on this screen.

After this, i plugged my HDD again, booted from SSD, stuck at this screen. i restarted, booted from HDD and it also stuck at this screen.

Now i am unable to boot.

Now what do you suggest Sir @Going Bald ?

My End Goal is to Install High Sierra to SSD and win10 to HDD.

Thanks

 

[Going Bald]

Hi, i used free version of CCC to clone my HDD to SSD. After clone, i installed clover to SSD and copied EFI folder from EFI partition on my HDD to SSD. My High Sierra successfully booted from SSD.

Now, i wanted to install windows on HDD for dual boot. therefore i unplugged HDD sata cable and tried to boot from SSD Alone. But i was stuck on this screen.

View attachment 434963


After this, i plugged my HDD again, booted from SSD, stuck at this screen. i restarted, booted from HDD and it also stuck at this screen.

Now i am unable to boot.

Now what do you suggest Sir @Going Bald ?

My End Goal is to Install High Sierra to SSD and win10 to HDD.

Thanks

Reboot to UEFI/BIOS, set BBS boot order again to default boot Mac SSD. Save&exit, continue boot.
Ant time you disconnect/reconnect drives you should always check to make sure of BBS boot order.

 

[Going Bald]

Ok I changed one thing in the above instructions - formatted the USB with GPT instead of MBR. Now it shows on the boot list but when I try to select it as the boot choice it just jumps back to the boot list screen.

See post #1 & #444

 

[gudkarma]

@Going Bald thanks again for your help, but it didn't work:

View attachment 408983

As a "last resort", I removed the NVMe drive and still got the same error. I'm pretty sure the problem might be something I'm not doing, I just can't seem to figure it out...

I was having trouble as well. i had to pull out the nvm to get windows to install.

 

[oopsydaisy]

I was having trouble as well. i had to pull out the nvm to get windows to install.

This was my experience as well. There can be no mac formatted drives present for Windows to install. I wish I could have just disabled my NVME drive in Bios, but not possible, so pulled it for installation. Apparently, I'll have to do this whenever I run a major update in Windows, which should be rare.