Trouble installing Win 10 64 bit, MBR/BIOS. Partition needs to be GRT

Caledon Ken · 14 Jun 2020

Wow lots of action on this thread.

I second Lance1's idea about using Macrium to image your current install off to another drive. I would verify this Image as part of backup. I might even copy my data out as a copy and paste just for ease of access and I like being very sure my data is safe.

Then spunk's solution to clean and convert disk to GPT.

Then as was pointed out by NavyLCDR and Kyhi install your 64 bit windows.

I didn't see a setting in your BIOS (in manual) that I would normal see to boot legacy, CSM Support. The only mention of booting legacy appears on page 2-19 "Limit CPUID Maximum" which the manual says when enabled "Allows legacy operating systems to boot even without support for CPU's with extended CPUID functions.

Not sure how familiar you are with Macrium / diskpart but you have a very knowledgeable group of members here that can assist.

rogertsch · 14 Jun 2020

NavyLCDR said:

Since the old system is 32-bit and the new install is 64-bit, that won't work. It's impossible to create a Windows.old folder going from 32-bit to 64-bit.

Yes, 64-bit Windows can certainly be installed on an MBR drive, but Windows.old folder cannot be created.

So, the best thing for me to do if I want to boot using UEFI Bios I must make that change in the Bios for the system to boot using UEFI compatible option and not the Legacy Bios option and then do a clean install of Win 10 64bit in a GRT partition. But will Win 10 SETUP give to option of how to create partitions if the Drive is clean of everything or should I format it before running the Win 10 install setup??

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Megahertz said:

On a computer that has UEFI BIOS, Windows 64 bits can be installed as Legacy - MBR or UEFI - GPT.
- To install as Legacy - MBR you MUST boot the installation drive as Legacy
- To install as UEFI - GPT you MUST boot the installation drive as UEFI.

For what I see from post #1, you have a windows 32 bits installed as Legacy-MBR and you are booting the installation drive as UEFI. When you try to install as UEFI on a MBR drive you get the message “Windows cannot be installed to this disk. The selected disk is not of the GPT partition style”.

To install Win 10 64bits on the MBR drive and create the Windows.old folder, you must boot the installation drive as Legacy, not UEFI.

So, the best thing for me to do if I want to boot using UEFI Bios I must make that change in the Bios for the system to boot using UEFI compatible option and not the Legacy Bios option and then do a clean install of Win 10 64bit in a GRT partition. But will Win 10 SETUP give to option of how to create partitions if the Drive is clean of everything or should I format it before running the Win 10 install setup??

NavyLCDR · 14 Jun 2020

rogertsch said:

So, the best thing for me to do if I want to boot using UEFI Bios I must make that change in the Bios for the system to boot using UEFI compatible option and not the Legacy Bios option and then do a clean install of Win 10 64bit in a GRT partition. But will Win 10 SETUP give to option of how to create partitions if the Drive is clean of everything or should I format it before running the Win 10 install setup??

First, since Windows setup is requesting a GPT drive, you are already booting it in UEFI which would then complete the install and reboot in UEFI mode.

Since you need to switch to GPT and going from 32 to 64 bits, you really need to delete every partition on the drive at the screen after selecting the custom install option until you have only one big unallocated space on that drive. Highlight the unallocated space and then click next. You don't need to manually create any partitions or format anything.

Caledon Ken · 14 Jun 2020

Once you are ready to install, after using diskpart to clean and convert GPT, Windows will handle and if disk is GPT your system should default to UEFI.

Recommended to only have the SSD connected when clean installing so Windows doesn't do something strange. (Which has happened.)

rogertsch · 14 Jun 2020

Caledon Ken said:

Once you are ready to install, after using diskpart to clean and convert GPT, Windows will handle and if disk is GPT your system should default to UEFI.

Recommended to only have the SSD connected when clean installing so Windows doesn't do something strange. (Which has happened.)

Thanks alot Ken, it's great there are people like yourself who take the time to help others.

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NavyLCDR said:

First, since Windows setup is requesting a GPT drive, you are already booting it in UEFI which would then complete the install and reboot in UEFI mode.

Since you need to switch to GPT and going from 32 to 64 bits, you really need to delete every partition on the drive at the screen after selecting the custom install option until you have only one big unallocated space on that drive. Highlight the unallocated space and then click next. You don't need to manually create any partitions or format anything.

Thanks a lot, NavyLCDR, it's great there are people like yourself who take the time to help others. I think I'm now confident in doing what you have suggested. I just wanted to be sure of things before I ran into so much trouble that I could not come back from, I'm sure you know what I mean. Thanks again.

spunk · 14 Jun 2020

To Add to what is being said, When you choose Custom Install in the Windows Installer, then in Where to Install Windows, you Delete All Partitions. If you booted using the UEFI Bios with your installer, Windows will automatically Initialize the drive GPT from the previous MBR, then just press Next. Windows will automatically create Partitions and format them during the install.
This is a Clean Install. A Windows.old folder is only created when Upgrading from Within Windows (ie) upgrade from Windows 7 or an earlier version of Windows 10 to the current version of Windows 10.
As stated, you cannot Upgrade to 64 Bit Windows from 32 bit, you must do a Clean Install.

Megahertz · 14 Jun 2020

rogertsch, why do you want to create a Windows.old folder (post # 5) when installing Win 10 64bits? Is to have your data available (windows.old\users\Name)?

Berton · 14 Jun 2020

Something else to be aware of [didn't see it mentioned]:
https://support.microsoft.com/en-us/...rger-than-2-tb

Megahertz · 14 Jun 2020

NavyLCDR said:

Since the old system is 32-bit and the new install is 64-bit, that won't work. It's impossible to create a Windows.old folder going from 32-bit to 64-bit.
Yes, 64-bit Windows can certainly be installed on an MBR drive, but Windows.old folder cannot be created.

NavyLCDR, how a super star Guru like you be so WRONG.

What I wrote works as I described.
- If you have a Windows 10 32 bits installed as Legacy-MBR and you boot the Windows 10 64 bits installation drive as Legacy, and choose to install on same partition of the Windows 10 32 bits, a Windows.old folder will be created with all Windows 10 32 bits folders.
I confess that your affirmation that I was wrong put myself in doubt.
So I downloaded a Win 10 1909 32 bits iso and made a USB legacy boot able drive.
I installed Win 10 1909 32 bits on a spare drive and then I've installed Win 10 2004 64 Bits.

Trouble installing Win 10 64 bit, MBR/BIOS. Partition needs to be GRT-install1.png

It did created a Windows.old folder as OP wanted (See post #5).
All this effort just to prove myself (and to others here) that I was right (and you Wrong).

Trouble installing Win 10 64 bit, MBR/BIOS. Partition needs to be GRT-tree.png

I've seen that you frequently quote others post and say "You're wrong".
Not very polite to your colleagues at the Forum, and sometimes, not always, you're the wrong person.

NavyLCDR · 14 Jun 2020

Well, @Megahertz, thank you for correcting my error. I only want the accurate facts to be presented. And when I do see posts that I am almost certain are incorrect, I will continue to post the correct information, consider it rude or not. But I, like others, do make mistakes.