Windows 10 two instances / dual boot

dbrook007

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Jan 9, 2009
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Hi,

I need to have two bootable instances of Windows 10 Pro 64-bit on my PC.

I have one installed already and intend to have the other Windows 10 on a separate physical drive.

So, what's the best way to do this?

All accounts on the PC will be local accounts, not Microsoft accounts.

I do not want the settings etc of each Windows to reflect the other. I also do not want this affect the performance of the PC under the current Windows 10 installation in any way.

Do I have one or two options?

My first thought was to disconnect the current o/s drive, connect the new one there and install Windows as usual. Then, I could select which drive to boot from via the BIOS boot menu. My motherboard is an Asus X-99 Deluxe II. You can request this menu by pressing F8 when the BIOS polls for F2 keypresses to enter the BIOS main UI.

But, does this method work reliably? Are their any pitfalls to this method?

But from what I've read, I can also do a more typical dual-boot and select to install the 2nd Windows 10 on a different physical drive. Is this correct?

Does doing it this way have any implications or effects on the current installation? I suppose what I am concerned about is, if Windows "knows" there is more than one installation, I don't want it doing anything in the background. I need to keep my current install intact.

Again, what are the pitfalls of this way of doing it?

I'd appreciate any helpful advice.

Thank you.
 
Solution
Yes.
Install each OS with only that specific drive connected.
Select which one in the BIOS during boot up.

I have done exactly this.

While you are running OS #1, it will see the 'other drive' simply as a secondary drive letter....the D, for instance.
Doesn't matter which one...it will see itself as the C drive, and the 'other drive and OS' as a different drive letter.
They will not interact or care. Just don't change any windows files on the 'other drive'.
If I were doing it I would do it via your first suggestion (I have done it that way several times) and disconnect the current installation of Windows 10 and just install your second instance of Windows 10 onto the other hard drive. Also, this is very important, make sure that fast boot is disabled in BIOS and within the Windows 10 settings make sure you choose not to sync your installations. I learned that lesson the hard way in the past.
 

USAFRet

Titan
Moderator
Yes.
Install each OS with only that specific drive connected.
Select which one in the BIOS during boot up.

I have done exactly this.

While you are running OS #1, it will see the 'other drive' simply as a secondary drive letter....the D, for instance.
Doesn't matter which one...it will see itself as the C drive, and the 'other drive and OS' as a different drive letter.
They will not interact or care. Just don't change any windows files on the 'other drive'.
 
Solution

dbrook007

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Jan 9, 2009
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Hi, thanks. Why does fast boot need to be disabled? What impact does this have on my current Windows installation?

On the sync, is this only relevant if you are using Microsoft accounts (all mine will be machine/local accounts) ?

Thanks
 

USAFRet

Titan
Moderator


"Fast boot" is often too fast for you to interrupt the boot process and get to the BIOS to be able to select the desired drive.
 

dbrook007

Distinguished
Jan 9, 2009
39
0
18,530


The current Windows 10 is on an NVME on the board, not an SSD via sata... how does that affect or change things, if at all?

Are the NVMEs easy to remove/put back in?
 

USAFRet

Titan
Moderator


Yes, easy to disconnect.
A couple of screws.

Power off, obviously.