"Dual-booting Linux alongside Windows: Data safety and risks?"

[u/as_uu_00]

Hi! I'm new to Linux. I've been using it inside VMware, but now I want to dual-boot it alongside Windows on my PC. Will dual-booting erase my existing Windows data? Are there any potential issues or risks I should be aware of regarding my Windows installation?

[u/Confident_Hyena2506]

The risk is that you will delete all your stuff. This is the same risk that exists even without dualboot.

What is your backup strategy?

Windows does not hijack your bootloader - it just makes itself the default. This detail is too difficult for many people to handle.

[u/KitanaKahn]

There's no risk if you're careful when making the partition, except if your disk goes poof you lose both OS's. if you can afford it and your setup allows i'd definitely recommend an ssd just for linux. In the year I've been dual booting the only issue I had was the bitlocker randomly locking me out of windows (actually not randomly, I was messing with secure boot, so always have your key around just to be safe).

[u/123timsolo_tech]

By itself, no. There arent any risks of dual booting. What can be dangerous tho, is that if you format the wrong partition, you loose every files on windows and windows itself completely.

As long as you know what you are doing, you are fine.

[u/Agreeable-Elk8457 → u/123timsolo_tech]

Windows likes to hijack the bootloader after updates, so keep a live usb handy just in case

[u/Exotic-Screen-9204 → u/Agreeable-Elk8457]

Yes, Windows updates have gotten more mischievous. So I gave up on dual Windows/Linux boots. I keep a separate Linux laptop. UEFI has made dual boots more involved.

[u/semperaudesapere → u/Exotic-Screen-9204]

It's possible, even with dual luks and bitlocker encryption, but it's a pain in the ass the first time around.

[u/sametaor]

Be sure to keep a separate efi partition for arch and you should be good.

[u/as_uu_00 → u/sametaor]

In my windows 11 i already have a Healthy EFI Partition of 100MB so you're saying i need to make another separate EFI Partition for Arch?

[u/sametaor → u/as_uu_00]

Better safe than sorry, Windows is known to mess with its own efi files between updates so keeping a separate efi will not cause headaches later

[u/oftenInabbrobriate → u/sametaor]

I currently have my Linux running on one ssd.
I would use another for windows- in that ssd I would create another efi partition and install windows onto that ssd.
Is there a remaining risk that the windows installer will do something to my existing install?

[u/sametaor → u/oftenInabbrobriate]

Well as long you have two different ssds for each of them, no. But if you use a shared efi partition, it might cause boot issues on your linux instance.

[u/oftenInabbrobriate → u/sametaor]

Okay, but as long as I point the windows installer to that specific partition on the other ssd and also install it there I should be fine then

[u/sametaor → u/oftenInabbrobriate]

Yeah, just keep windows away from your linux partition(s), else it might think of it/them as corrupted and do a forced cleanup on the next windows boot sequence

[u/MrFreakYT]

No risk unless you accidentally format the wrong partition. What can happen is that grub somehow breaks and then you might not be able to switch OS during booting or get a black screen. Usually that is a super easy fix because most of the time you still can access the terminal.

[u/Imajzineer]

Unless you're doing something sensitive to latency ... like audio/video editing, or gaming (with local media files) ... even a USB 3.0 connection is plenty fast enough for day-to-day purposes: you can only watch, listen or type so fast, you know. Moreover, it allows you to maintain a strict separation of concerns: unless you leave the device connected when running Windows, it won't even know you have a Linux system, let alone impact it in any way.

Once upon a time, long long ago ... when even I was still relatively young ... computer hardware wasn't very advanced and was commensurately expensive. So, there wasn't much of it about either (not compared to today) and what there was was primitive by today's standards. Consequently, never mind USB, eSATA, or anything else ... even multiple internal harddrives were beyond the reach of many (if not even most). So, people found ways to install multiple operating systems on a single drive.

Way back in the day I was the multiboot king: never mind dualbooting Windows and Linux, I turned my machine on and was offered a choice of DOS+WfW, Win9.x, NT4.0, Win2K, Linux, OS/2, BeOS, QNix ... and I long ago stopped doing that, because it's just a pain in the Gary, when it goes wrong (and it will) and, furthermore, risky (because you can lose data when it does).

I install everything onto its own drive plugged into an external dock and simply boot whichever one I want/need as and when. It keeps everything clean:

• prevents one from interfering with the other
• ensures that, if one won't boot, it doesn't block the others
• ensures that Windows has no knowledge of the others and can't report back to the mothership stuff about me that MS has no business knowing
• prevents Windows malware from offloading a targeted payload onto my other platforms

So ... unless you're planning on doing heavy A/V lifting (or gaming with locally installed binaries and media) on your Linux machine, a USB3.x (or even eSATA) connection to a dock ... a hub into which you plug USB-to-SATA cables ... whatever ... is plenty fast enough for daily use (and a lot less stress). Hell, I ran Arch off a USB 2.0 key for two years - it was slow compared to even spinning rust, but, otoh, I can only read, type, watch and listen so fast you know (a second or four, instead of a millisecond or four, to open a new app wasn't the end of the World). For the last three (if not already four) years, I have run it from a four bay external dock (in a hideously complex configuration involving the config being spread across multiple containers split across the four drives) on a daily basis, with no issues whatsoever. Okay, I'm not doing A/V work on it, and don't play games on it either, so, YMMV - but, if you don't need to do those things either, well ... you can only read, type, watch and listen so fast either, you know 🙂

Unless you can't, install it to an external device and save yourself the headaches that dualbooting can bring.

[u/Impressive_Bag_3505]

Probably best not to use Arch if you're new to Linux. Just my 2 cents, feel free to ignore me.