Erased Boot Drive When Installing Windows

[Alabrel]

Whoops.

I'm really not sure how it happened, but I guess Windows did it behind the scenes? I read that you should physically remove the other drive from your cpu but I thought, nah, I got this. Now it no longer has the UEFI boot in the boot options, and instead Windows Boot Manager is listed as an option for my Crucial SSD, even though I told Windows to install on my HDD.

Now I can't boot anything Mac related. Booting from "Recovery HD" or "Sierra" brings up the start up screen, but it never loads. If I reinsert my Unibeast Boot drive and try to go from there, I get an circle with a slash through it.

I reset the Windows side thinking it'd format the drive so I could start over, but it still shows the Windows boot manager on the SSD, and now I (of course) can't boot Windows either. I assume I'll have to do a fresh install of Windows, but I don't know where to go from there. How do I start over?

EDIT: Used a Windows installer to erase the drives. *sigh* still getting the circle with the slash. Gonna try to redo the bootable USB and try some various boot options and BIOS settings, but I don't get why it stopped working when it was just fine before.

EDIT 2: Redoing the Unibeast USB is doing the trick. Time to start from the top. *sigh*

 

[Jamesbond007]

Whoops.

I'm really not sure how it happened, but I guess Windows did it behind the scenes? I read that you should physically remove the other drive from your cpu but I thought, nah, I got this. Now it no longer has the UEFI boot in the boot options, and instead Windows Boot Manager is listed as an option for my Crucial SSD, even though I told Windows to install on my HDD.

Now I can't boot anything Mac related. Booting from "Recovery HD" or "Sierra" brings up the start up screen, but it never loads. If I reinsert my Unibeast Boot drive and try to go from there, I get an circle with a slash through it.

I reset the Windows side thinking it'd format the drive so I could start over, but it still shows the Windows boot manager on the SSD, and now I (of course) can't boot Windows either. I assume I'll have to do a fresh install of Windows, but I don't know where to go from there. How do I start over?

EDIT: Used a Windows installer to erase the drives. *sigh* still getting the circle with the slash. Gonna try to redo the bootable USB and try some various boot options and BIOS settings, but I don't get why it stopped working when it was just fine before.

EDIT 2: Redoing the Unibeast USB is doing the trick. Time to start from the top. *sigh*

If you instruct Windows to install itself on the second hard disk, my understanding is that it will still install its boot code on the first hard disk (and not the second disk) if one is present, and therefore overwriting the Clover bootloader on the first disk. This is probably why you have problems booting MacOS after installing Windows.

So I believe you understand now why we always recommend disconnecting other disks when attempting to install Windows? In fact if I were you, I would start by first installing Windows on the HDD, then disconnect it and attach the SSD, and install MacOS. After MacOS configuration is completed and can boot, finally attach the HDD as the second disk.

As you are using a Gigabyte motherboard, you may not have to physically disconnect the drives to achieve the "disconnect" effect. The UEFI bios of the Gigabyte motherboard has a useful function where you can selectively disable and enable individual SATA ports. For instance if you want the system to only see the HDD you can temporarily disable the SATA port where the SSD is connected to (assuming you are using a SATA SSD) and vice versa.

 

[BreBo]

EDIT 2: Redoing the Unibeast USB is doing the trick. Time to start from the top. *sigh*

Guide: Multibooting UEFI on Separate Drives

 

[Alabrel]

Got it this time around! Thanks!