Dual boot with two drives that already have an OS on them.

Pendaws · 07 Feb 2022

I have Win10 on my main HDD and on another HDD (same size and manufacturer) I have a copy of Win11.
What I want to do is find out if it it possible for me to put the other drive in my machine permanently and dual boot.
I know I should have done it the regular way but issues have made that a little hard.
Both drives have had the OS installed on the SAME machine so no compatibility issues but, I want to find out if there is a way to do what I want to or, do I have to wipe the 11 drive and reinstall the OS with the Win10 drive as first one.?

Thanks in advance for any help.

cereberus · 07 Feb 2022

Sure you can put both drives in.

1) put both drives in and go to bios to select to boot from Windows 10 drive.

2) run admin command prompt and type

bcdboot #:\windows

where # is drive letter of windows 11 drive as seen from Windows 10.

AddRAM · 07 Feb 2022

Or just bring up the Boot menu when you want to use the other drive.

Megahertz · 07 Feb 2022

AddRAM said:

Or just bring up the Boot menu when you want to use the other drive.

The best solution.
Different drives, each with it's own and independent OS.

NavyLCDR · 07 Feb 2022

Megahertz said:

The best solution.
Different drives, each with it's own and independent OS.

I would disagree. First, if Windows 10/11 fast startup is enabled, it interferes with the ability to press whatever hotkey is assigned to bring up the BIOS or UEFI menu to select which drive to boot from.

Second, I have 2 laptops and one desktop computer. They have three different keys to bring up the BIOS (UEFI) boot menu, F12, F11 and F8. It's totally inconvenient to have to remember which key I have to press on which computer to bring up the menu, and hope that I tap the key at just the right time in the power-on sequence to get the menu.

Third, you can maintain the ability to independently boot each drive with its own independent OS and also have the convenient Windows multi-boot menu. I can have Windows 10 on one disk, Windows 11 on a second disk, and each disk can have its own EFI System Partition (or active partition with legacy BIOS) which contains a BCD that allows me to dual boot, regardless of which physical disk the computer's BIOS (UEFI firmware) boots from.

AddRAM · 07 Feb 2022

We`re only talking about 1 PC here, not 3.

Why would you have to use the Boot Menu key on all 3 of your PC`s ?

I could see maybe having a dual boot on the desktop, but on the laptops too ?

And if your memory is that bad, just watch the screen

steve108 · 07 Feb 2022

Yeah , @NavyLCDR, what's wrong with you?

NavyLCDR · 07 Feb 2022

steve108 said:

Yeah , @NavyLCDR, what's wrong with you?

I'm lazy. I like to do things the easy way.

steve108 · 07 Feb 2022

NavyLCDR said:

I'm lazy. I like to do things the easy way.

I represent that remark

NavyLCDR · 07 Feb 2022

AddRAM said:

We`re only talking about 1 PC here, not 3.

Why would you have to use the Boot Menu key on all 3 of your PC`s ?

I could see maybe having a dual boot on the desktop, but on the laptops too ?

And if your memory is that bad, just watch the screen

Well, let's see. I can turn the computer on, repeatedly press F12 at just the right time, wait for the BIOS boot override menu to show up, then pick the correct drive from the cryptic descriptions that show up.

OR

I can turn on the computer, get a boot menu that has entries "Windows 10" and "Windows 11". If I wait 3 seconds, Windows 10 boots, or I can press down arrow and enter to select and boot Windows 11.

I like things nice and easy, so I will pick the second option. However, since both disks are set up with their own ESPs anyway, the first option is still available, if I choose to use it. It's called "the best of both worlds" or "having your cake and eating it too". Weak argument? I don't think so.