[Guide] Dual Booting Mountain Lion and Windows 8

[Going Bald]

I'm totally confused....
i have first instal OS X el cap...everything working...great..
now i try to install win 8.1 on same ssd...
i created partition in disc ut., as fat...on gpt-
but, on install screen, click on selected partition,
hit format.... an when i try to install, get this error:
windows cannot be installed to this disk.
the selected disk has an MBR partition table.
on efi system, windows can only be installed to gpt disks

thnx

do not format the partition for Windows as FAT - this creates a hybrid MBR partition and Windows cannot install UEFI on it.
Create the partition and format it as if for OS X.
At the Windows install screen select the partition, delete it and select the resulting free space to install Windows. The installer will take it from there.

 

[Sino1974]

do not format the partition for Windows as FAT - this creates a hybrid MBR partition and Windows cannot install UEFI on it.
Create the partition and format it as if for OS X.
At the Windows install screen select the partition, delete it and select the resulting free space to install Windows. The installer will take it from there.

so...in disk util., format as standard for osx? extended-journaled
on install screen win 8, delete? not format?
just to be sure...

thnx

 

[Going Bald]

You got it. Really think you need a separate drive for Windows.

 

[Sino1974]

You got it. Really think you need a separate drive for Windows.

...now it works..
Yes...will install second sdd for windows,...for sure

Thanx for help

 

[josh.jennings]

I'm having trouble with my dual boot. I have a GA-Z97-HD3 and i5 4690K. Monitor is plugged into DVI on my GTX 960. OS X is on a SSD and Windows 10 is on a HDD. When either are plugged in alone, everything boots and operates fine. When they are both plugged in, Clover launches correctly, and I see my OS X drive along with 4 or 5 other Windows drives. I can then select my OS X and it boots fine. However, if I select the Windows drive that says something like "Windows EFI on EFI" I get the black screen with the spinning white dots for about 10-20 seconds and then my screen goes black with no cursor (i.e. no signal).

I originally installed Windows 7 on the HDD and then upgraded to 10. Just for the sake of completeness, I checked msinfo32, and it is indeed UEFI.

 

[Going Bald]

I'm having trouble with my dual boot. I have a GA-Z97-HD3 and i5 4690K. Monitor is plugged into DVI on my GTX 960. OS X is on a SSD and Windows 10 is on a HDD. When either are plugged in alone, everything boots and operates fine. When they are both plugged in, Clover launches correctly, and I see my OS X drive along with 4 or 5 other Windows drives. I can then select my OS X and it boots fine. However, if I select the Windows drive that says something like "Windows EFI on EFI" I get the black screen with the spinning white dots for about 10-20 seconds and then my screen goes black with no cursor (i.e. no signal).

I originally installed Windows 7 on the HDD and then upgraded to 10. Just for the sake of completeness, I checked msinfo32, and it is indeed UEFI.

There should be one labeled something like Boot Windows Boot manager on EFI - use this one

 

[josh.jennings]

I found (and have been using) "Windows EFI boot menu on EFI." The other options are "Windows on EFI" (which does absolutely nothing), "Windows on Legacy HD3," and "Windows on Legacy HD4." And the legacy options are obviously not right.

 

[Sino1974]

You got it. Really think you need a separate drive for Windows.

hello again,
i took your advice, and i have plan to install second ssd for windows only, think is gonna be same as old, 240 gb.
now, what is the best option to make it work?
Now i have one ssd 240gb with dual boot, osx and win 8, but im gonna delete second partition, and leave just osx on that drive.
On second drive is plan to have only win 8.
How to?
i saw that there is some raid option for two ssd, but im not so much in this, so be so kind and give some advice.

Thnx,
S

 

[Going Bald]

hello again,
i took your advice, and i have plan to install second ssd for windows only, think is gonna be same as old, 240 gb.
now, what is the best option to make it work?
Now i have one ssd 240gb with dual boot, osx and win 8, but im gonna delete second partition, and leave just osx on that drive.
On second drive is plan to have only win 8.
How to?
i saw that there is some raid option for two ssd, but im not so much in this, so be so kind and give some advice.

Thnx,
S

Disconnect OS X drive
Connect Win8 to be drive
Install Win8 UEFI mode
Reconnect OS X drive
Boot to UEFI and set OS X drive first in boot order
Save & exit, continue boot.

 

[PatrikMajer]

Hello I did not find any clear answer. If I have already installed win10 and I dont want to erase him Can I install osx ? Thanks for quick answer