Dual boot Ubuntu and Windows

Hi sir, I have a pc with 128gb SSD and 1TB HDD (partitioned in 600-400 GB) I have installed Ubuntu on pc such that /root files on my ssd and all /home files in 600 GB partition keeping 400GB extra. Now I want to install windows along Ubuntu (dual boot) can you tell me the best way??:slightly_smiling_face:

It is almost essential, if you have already installed Ubuntu, to put Windows on a different disk to what Ubuntu is on.
So I would install Windows on the HD. I think Windows needs the first 2 partitions on a disk, so you may have to move your
/home partition.
Someone will correct me if I am wrong on that.

After you have installed Windows on HD, you can use the BIOS to point to which disk you want to boot…
Point it to the SSD and boot Ubuntu.
Then in Ubuntu do
as superuser,
and it will hopefully find both Win and Ubuntu and construct a new grub menu for you.
If it does not find Win, ask us, there is a fix.

Then reboot and you should get a grub menu offering you a dual boot with Ubuntu and Win as options.

Before you do anything do a FULL BACKUP to some external medium.
A backup is essential… a zillion things can go wrong during any install.



If you plan to use Windows I think it’s better to have it on the SSD too.
I’d make the room for it: shrink Ubuntu partition, move the /home to the HDD, and such…
I’d empty about 60…70GB on the SSD to install Windows there.
I’d create a data partition on the HDD for Win too, and after the install finished, move your user data folders there. There are tricks to move the complete usere and settings dir to another partition during install, you can google for it.
After you have installed Windows, 99% you will need to reinstall GRUB.
Don’t forget to enable OS prober, if you have a recent Ubuntu, as they have it disabled by default. After that you should be able to dual-boot via the GRUB.
Possibly, it’s good to have GRUB protected against bigger Windows upgrades, the trick is, that make Windows boot manager the first entry in the EFI boot order, just make it inactive.
So your EFI will always boot the second entry, which is GRUB, Windows just checks itself to be the first entry in the order list, doesn’t check to be active as well
So you can sleep well, Windows upgrades will not kick GRUB from the boot order…


Move Ubuntu to the HDD and install Windows in the SDD. Use the machines bios and set the HDD to boot first and update-grub.

  1. Perhaps getting a second SSD is a good idea. I’ll explain later why.
  2. Install Windows, give it a SSD.
  3. Install Linux, give it the other SSD. Make sure to configure /home to be on the HDD.

The reason why I suggest a separate SSD for Linux, is that now you can use your UEFI’s boot menu to select which OS to boot. Also, Windows’ bootmanager and Linux’ boot managers don’t like one another. Putting them both in the same partition will result at one time or another in an unbootable OS’ (either Linux or Windows).

Windows update will also not help the situation. It is known for eating other OS’ boot-files.

The reason I say get another SSD, instead of putting Linux on the HDD, is because it can really hamper performance of applications. If you’re the patient type, it does not matter. I nearly destroyed my computer at one time because an application was waiting for some more stuff to be loaded. Documents on a HDD is not much of an issue, actual executables and libraries is.


I am not in disagreement with my fellow experts… But

Windows needs the SSD for speed loading and running it’s a dog on a normal hard disk, sorry I clarify its more of a dog.
So the but, 128 is about enough for windows today but once you start loading apps or doing the daily updates you will run out of space very quickly and have nothing left to store documents.
Ideally partition your hard disk in 2 one will be just for data use.
Do a clean install of windows onto the SSD then having split the hard disk re install Linux on one part of the hard disk.
Linux runs faster and has no issues reading the windows partition on the hard disk but windows may do
Clean installs from scratch save trying to change the grub.
Yes the ideas given above will work and they are correct in the advice given I just prefer simple solutions


Welcome to the forum @Koustabh_Ghosh. I hope you enjoy your visits here.

You have received some very good advice / options from the comments so far. In configuring your PC, it also depends on how you going to use it and which OS are you going to use the most. If you are going to be bouncing back and forth between Windows and Ubuntu then my vote would be to place both OS’s on the 128 GB SSD. The SSD is a bit small, but both OS’s can easily fix on it.
To put both OS’s on the SSD, you might have to install Windows first and then re-install Ubuntu. As someone else already said, be aware having both OS’s on the same disk can cause conflicts in the EFI partition.

I would then use the HDD for my data for both Windows and Linux.

Whatever you decide, have a backup and restore procedure in place. Having a good backup and knowing how to restore the backup can save a lot of time and frustration. This goes for both your OS and your data. BTW, I also backup the EFI partition.


I agree, a second SSD is the best solution.

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The ONLY PROVEN way to RELIABLY have dual boot of Windows and ANYTHING else is to put Windows on a physically separate drive from ANYTHING else and use BIOS to boot from whichever OS you like.


After fifteen or so years of double booting, I finally bought a medium HP desktop with Windows and loaded it only with games. I scratch-built a nice machine for much less and use it for Linux and all my important work. They’re connected to a keyboard/mouse/monitor through a nice KVM and everybody gets along.

Except when I try a distro that steals the whole drive and doesn’t play well with others–those fringe distros just go on the scrap heap.

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Those nasty distros, eg Intel Clear Linux, are OK in a VM.

No argument there. But if I choose to test one over a couple of weeks, I’d rather install it so that I can use it to address my external drive, my NAS, and maybe even my printers–can’t do that from Boxes.

And, no, I’ll continue to use Boxes instead of fancier VMs. The simple life is the life for me!

I think you may be able to?
You can do it from virt-manager, and it is qemu/kvm the same as boxes.
I must admit I could not do it when I last had boxes, but I have
learnt a bit since then. Might be worth another look.

There is some hope


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