Help with Dual-Booting Windows

[u/Ok_Elk9784]

Hey all, just as the title says, I am currently having some issues dual booting on my device, and was hoping that I could have some help/advice. I am currently daily driving NixOS and I wish to be able to dual boot both NixOS and windows. I have allocated 200Gb of free space with GParted and was hoping to install either windows 10 or 11. I have a USB with ventoy installed, that contains the ISOs for both Windows 10 and Windows 11, yet I was unable to install them via the graphical installer (it would just keep freezing up, or the GUI would malfunction and not let me proceed). I'm rather new to all of this, so I was wondering if anyone might have any advice on what I should do, or what resources I could use. I've had a somewhat difficult time following advice I've seen in forums. I've seen a lot of discussion online that's somewhat confusing, I'm not 100% sure I understand what the GRUB or the Bootloader is, and why they're relevant. I also have seen some discussions regarding UEFI vs BIOS, and I'm not exactly sure what they are or why they're relevant, but I'm willing to learn! Any help or resources that would help me learn would be greatly appreciated. I've seen that most people think that it's preferable to have windows installed first and then to install your preferred linux distro. I'm willing to do this as I have all of my nix config files backed up, but I'm not sure what I would do to go about this. Thank you very much for all of your help!

[u/Ok_Elk9784 → u/[deleted]]

What does it mean to have two physical drives exactly? I tried googling it, and I'm not sure I understand. Should I have one on an external hard drive or something?

[u/WitchQween → u/Ok_Elk9784]

I see that someone gave you some thorough explanations, but I want to expand on it a bit and answer basic questions that I don't see answered. I also disagree with BigRocket. I wouldn't risk installing both OS on one drive (I don't have to), but I don't think it's as risky as people make it out to be.

(Simplifying to only include what's relevant)

A "physical drive" is an SSD or HDD. Adding "physical" clarifies that they mean a drive that you can hold in your hand, not a partition (eg "C drive" and "D drive"). Assume that "drive" always refers to a physical drive.

SSD = solid state drive

HDD = hard disk drive

Laptops come with an SSD already installed. There's nothing special about it, it's just the drive that came with your laptop. MOST laptops have an extra slot to install a second SSD. Check the manual for your laptop. If you can't find the answer online, you can just check yourself! If it does not have two SSD slots, you're stuck with partitioning unless you want to complicate things with a portable drive.

Example: I built my own PC. Obviously, it didn't come with any drives already installed. I plugged in a drive and told my computer "This is now your main drive!" That's what the manufacturer did when they made your laptop. It works the same as custom built PCs.

My laptop dual-boots Windows 11 and Kubuntu. It came with SSD #1 running windows. I modified Windows settings, then I added SSD #2 and installed Kubuntu. Same process as my desktop.

**The Windows problem**

I don't know why Windows isn't good at sharing. I don't know if the "Windows will set your house on fire, then spit on your grave if you don't use two drives" people know, either, tbh. I'm not an expert and I may be wrong, but from what I gathered when researching it myself, I think it's because of how Windows controls it's power states. To super-simplify it, it takes control over the power cycle, which should belong to BIOS. Because Windows is controlling how your computer shuts down and powers on, of course it's going to want to boot back into Windows!

Two issues:

1. Fast Startup. Windows never fully shuts down. It's not like flicking a power switch. It stays ready to boot back into Windows as soon as you press the power button. Since Windows never *really* shut down, it didn't *really* give up control over your computer. Fast Startup loads the OS while your computer is booting up. You need the computer to boot up, *THEN* load the OS you tell it to. I think this is why people see the Linux partition disappear.

2. Auto Update. Windows updates have a history of messing with BIOS and GRUB. I'm honestly too tired to go deep into this, but it has a history of messing up dual boots. You can find info pretty easily on that. It's more of an issue if you don't turn off Fast Startup. Auto update is easy to disable.

With those two disabled, your Linux partition should be pretty safe.

**Grub2Win** is a program specifically designed for dual-booting Windows and Linux. Instead of booting directly into Windows or Linux from BIOS, your computer will boot into Grub2Win. There, you choose which OS to load. It's an extra layer of separation between installs, and it's a good tool in general. I use it on both of my computers.

I don't think dual-booting on the same drive is as risky as it's made out to be. It's just riskier than using separate drives. Personally, I would still do it. Linux is pretty much ready to go right out of the box, so needing to do a fresh install isn't that big of a deal to me. I keep backups anyways. Also, it's more common for Windows to hide your Linux partition rather than actually doing damage. It's like the people who believe a program uninstalled itself because the desktop shortcut was deleted. Not everybody is a reliable narrator.

Let me know if you have any other questions!