Can't Install Windows 10 to a GPT Partition

[LarryL5L]

I'm pulling my hair out here.

 

PROBLEM:

Can't install Windows 10 x64 from an OEM disk ... to a Samsung 850 EVO 500Gb SSD ... on a GPT partition. It installs instead on a MBR partition.

 

SPECS:

Motherboard: Gigabyte GA-Z170X-Gaming 7

Bios version: F4

SSD: Samsung 850 EVO 500Gb ... bare and never used ... this is Drive 0 (aka Drive C)

Media: Windows 10 x64 OEM disk

i7-6700K

 

WHAT I DID: In the bios I set "Windows 8/10 Features" to "Windows 8/10" and set "CSM Support" to "Enabled" (default). I inserted the windows 10 disk into the DVD drive. I booted and hit F12 to set the boot priority to the DVD drive ... F12 detected the SSD and 2 instances of the DVD drive ... one contained the UEFI string and the other didn't. (Note that if "CSM Support" is set to "Disabled" ... NO drives are detected.) I booted using the DVD drive with the UEFI string. Windows started to load but did not give me an option of HOW to format the SSD ... it only gave me the option TO format the SSD and no other information. In the end Windows 10 was installed on a MBR partition rather than a GPT partition. I tried this twice using bare and never used SSD's and had the same result both times. As I understand it ... if I boot to the DVD drive that contains the UEFI string and the Windows 10 disk ... Windows 10 should be installed on a GPT partition. Evidently I'm missing something.

 

QUESTIONS:

1. What am I missing ... how do I install Windows 10 on a SSD and a GPT partition?

2. Any particular bios settings to be aware of ... or something else such as software or drivers?

3. How do I delete all partitions on the SSD so I can start over?

 

When you reply assume I'm an idiot ... I'm really not ... but specificity is always helpful.

 

Thanks!

 

KenB

[airdeano]

i believe if you set up in your UEFI the SSD (boot drive) to the UEFI/SSD, this allows the switch to GPT partition.

otherwise, you'll prolly have to manually partition your drive.

 

 

try this method: https://forum-en.msi.com/index.php?topic=163500.0

 

Quote

Booting and partitioning of GPT for Windows 8/8.1/10: 
  1.Boot from the Windows 8/8.1/10 install media (You must initiate this boot from a device labeled as a UEFI device, or the installation of Windows 8 will produce an error that the OS cannot be installed to a GPT partition) These UEFI boot devices will have a prefix UEFI: "name of your device", and show as a boot option in your UEFI.
 2.After booting to the UEFI device you see the Install Windows 8 screen, press Shift + F10 to open a command prompt.
 3.Type Diskpart, press Enter
 4.Type List Disk , press Enter
 5.Type Select Disk # (where # is the number your drive shows up as), press Enter
 6.Type Clean, press Enter
 7.Type Convert GPT, press Enter
 8.Type Exit, press Enter.
 9.Close the Command Prompt window.
 10.Click the "Next" button.
 11.Click the "Install now" button.
 12.Put in your product key and click the "Next" button.
 13.Accept the terms and click the "Next" button.
 14.Choose "Custom: Install Windows only (advanced)."
 15.Select the partition and click "Drive options (advanced)"
 16.Click "New" and then click the "Apply" button. Four partitions should appear. Click the bottom partition.
 17.Click the "OK" button and then click the "Next" button.
 18.From then on follow the on screen instructions till you get to the desktop.
Note: If you can't boot after the install you need to make sure the boot is set to "Windows Boot Manager" in the UEFI. Also, important info.

 

[LarryL5L]

@airdeano

 

I have no clue what you just said! The more I read the more lost I get. Seems this should be a dead simple thing to do ... at the moment it seems like a complete mystery.

 

In my bios Boot Option 1 is merely listed as the SSD ... there is no UEFI string.

 

Sorry for all the questions ... just super confused ...

 

The procedure works on Drive 0 ... the drive that contains Windows? Isn't that where diskpart resides?

 

If I go through that procedure ... my SSD will be wiped of the MBR ... Windows 10 installed on a GPT partition ... and the SSD will have the UEFI string in bios?

 

How about my bios settings ... what should they be ... if one of them is incorrect ... wouldn't the installation revert to MBR rather than GPT? Note that if I don't have CSM Support enabled that none of the drives are detected.

 

Thanks!

 

KenB

[GoodBytes]

 -> CSM needs to be disabled. Enabling it, means: "Yes I want Compatibility mode, and want you to emulate the old BIOS"

 -> When you pick your USB flash drive or disk in the boot menu, if you see it in 2 variance for the same drive, where one has "EFI", or "UEFI" in the name, pick that one.

 

[LarryL5L]

But ...

 

This is how bios CSM Support is described in the manual ...

 

Enabled ... Enables UEFI CSM (Default)

Disabled ... Disables UEFI CSM and supports UEFI BIOS boot process only

 

When I set it to "Disabled" ... neither the SSD or the DVD drive (the only drives installed) are detected.

 

If it's set to Enabled ... I can hit F12 to set the boot priority where 3 drives are detected ... the SSD ... and the DVD drive twice ... one with the UEFI string and one without. I picked the one with the UEFI string ... YET ... Windows 10 installed on a MBR partition in the SSD.

 

So ... I'm still lost here.

 

Thanks!

 

KenB

 

 

[GoodBytes]

CSM means "Compatibility Support Module"

You use that with hardware or Operating System that aren't UEFI ready.

 

Make sure you have the latest BIOS/UEFI update installed, and disable Fast Boot (for now), and see if it detects your drives. Also try a different SATA Controller. Perhaps the one you are using isn't UEFI ready, but the other one is (generally the Intel one is)

 

Also make sure your SATA controller is set to AHCI mode.

[LarryL5L]

Yeah ... I know what CSM means ... but setting it to disabled does me no good if bios doesn't detect the drives.

 

I updated the bios from F4 to F7 (the most recent version that isn't beta). Fast Boot is disabled. AHCI is enabled. I dunno what to look at in regards to the SATA controller ... but nothing obvious pops out. There's only one listed in Device Manager.

 

I'm having a hunch that since the SSD is configured in MBR/NFTS ... that that's somehow effecting how the bios changes work.

 

I was able to delete the Windows 10 partitions on one of the SSD's ... but the SSD remains formatted as MBR. I had hoped to be able to try to install Windows 10 again but no sence trying until I can get out of this Legacy Mode trap.

 

Thanks!

 

KenB

[GoodBytes]

I don't know.

 

If you want to try something:

In Windows setup, do: SHIFT+F10 to open the command prompt

 

Then type and hit Enter: diskpart
Then type and hit Enter : list disk
Then type and hit Enter: select disk <disk number to convert> (without the '<' '>')
Lastly, type and hit Enter: convert gpt

 

Please note!

This will format all data on the drive. If you have an HDD or other secondary drive, unplug them before starting the process, so that there is no mistake. All partitions will be gone, in fact it has to be gone. So be sure you backup all your stuff, as every data will disappear.