A75 Extreme6 w/4tb HDD for OS, Windows 10 and UEFI

Hi. I want to upgrade from a 2tb HDD to 4tb. I've been having an enormously difficult time with this board on Windows 7 64-bit: freezing, crashing, failure to wake, and so on. I'm hoping that switching out the hard drive and moving to Windows 10 might help with some of this. However, when I try to install Windows 10 on my new 4tb drive, I am told that Windows won't install on my GPT-formatted drive. A little research suggests that motherboards have to have UEFI enabled in order to circumvent this. I am looking at the UEFI Setup Utility right now and am unclear on what to do to enable UEFI. It looks as though there is an option under the boot tab and then under "Boot Option Priorities" to put something called "UEFI: Built-I EFI Shell" as the first rather than the third boot option. I don't want to simply mess with this without some sense that this is the right move. Or is there some other setting I don't see that will allow me to run Windows on a 4tb hard drive on this motherboard? Thanks in advance.

Zaphod wrote: Hi. I want to upgrade from a 2tb HDD to 4tb. I've been having an enormously difficult time with this board on Windows 7 64-bit: freezing, crashing, failure to wake, and so on. I'm hoping that switching out the hard drive and moving to Windows 10 might help with some of this. However, when I try to install Windows 10 on my new 4tb drive, I am told that Windows won't install on my GPT-formatted drive. A little research suggests that motherboards have to have UEFI enabled in order to circumvent this. I am looking at the UEFI Setup Utility right now and am unclear on what to do to enable UEFI. It looks as though there is an option under the boot tab and then under "Boot Option Priorities" to put something called "UEFI: Built-I EFI Shell" as the first rather than the third boot option. I don't want to simply mess with this without some sense that this is the right move. Or is there some other setting I don't see that will allow me to run Windows on a 4tb hard drive on this motherboard? Thanks in advance.

First, I can tell you that the "Built-In EFI Shell" or "Launch EFI Shell from filesystem device" (another name for the same thing), will not enable UEFI mode, or help you install Windows 7 on your 4TB HDD.

Your board has a utility provided by ASRock called ASRock 3TB+ Unlocker Utility ver:1.1.1, on the Windows 7 download page. As you know, your 4TB drive must be GPT formatted in order to be able to address all of its space. The MBR formatting limit is normally 2.2TB. I've never used this ASRock utility, but it may format the HDD as GPT, and possibly also enable what I will describe next.

The "UEFI enabled" thing you mentioned is true to the extent that large drives need to use the EFI Option ROM that is part of the UEFI/BIOS file. There are a few ways to enable that manually, some simpler than others.

The easiest way is with a sub-option of the CSM option. This option appears when CSM is set to Disabled (default value), and is called "Launch Storage OpROM Policy", set to Legacy Only by Default. Setting this option to UEFI Only will cause the EFI OpROM to be used.

Where is CSM in your board's UEFI/BIOS? I don't know, the manual is not up to date IF the CSM option is available. You would need to have a later or latest UEFI/BIOS version installed on your board. My ASRock Z77 board, similar in age and generation to yours, has the CSM option in the ACPI Configuration screen, found in the Advanced section of the UEFI/BIOS. Newer boards have CSM in the Boot screen.

Regardless, try downloading and running the ASRock 3TB+ Unlocker Utility ver:1.1.1 from your board's Windows 7 download page (32 or 64 bit). That version of this program, 1.1.1, is still used currently with the latest Z170 boards, so you don't need a new or different version:

http://www.asrock.com/mb/AMD/A75%20Extreme6/?cat=Download&os=Win764

Install and run this program, which may be all you need to do. If you are still having problems, let us know. I've never used it since I install Windows in full UEFI mode, by setting CSM to Disabled. That requires your video source to be GOP compatible, which takes us in another direction. I don't know if your board (A75 chipset) ever had a CSM option available, the ASRock Z77 boards were some of the first ones to let us configure this option manually. Your board may have been excluded from this.

NOTE: Yes, an AMD board of this vintage (A75 chipset) will most likely NOT have the CSM option available for manual configuration (I doubt it will.)

The 3TB+ Unlocker program should be all you need. Using drives of this size is an advertised feature of your board.

Questions: Where, and when exactly do you see or get a message that Windows 10 cannot be installed on your 4TB drive?

What is the SATA mode set to in the UEFI/BIOS?

NOTE: IMPORTANT!! I just noticed your board has an ASMedia SATA chipset and two ASMedia SATA ports. Do NOT use one of those ports for an OS drive, or with your 4TB HDD. If you have the 4TB drive connected to an ASMedia SATA port, that might be part or all of the problem! Move it to an AMD SATA port.

i got my DVD drive to show up again, but still unable to install Windows on a 4tb drive.

Hi, All: I thought I would just check in with the solution. In the Bios, on the Exit tab, there is an option to "Save to UEFI Defaults." Always reluctant to click on something the effect of which I know nothing, but at wit's end, I clicked and then saved and exited. Lo and behold, Windows 10 finally installed on my GPT drive. The only downside is that Windows would only allow me to create a new partition out of only about half the hard drive. (I only needed about 100gb, not 2tb, on my OS (c:) drive. I have no idea why this worked. Any way, thanks for all the input and help.