I just got a new PC with Windows 10 on an SSD. With my previous PC I had two hard drives, one with Ubuntu 14.04, one with Windows 7. I dual booted flawlessly with that setup. Now, I have moved these two HDD's to the new PC, but I would like to know how I can use my HDD with the existing Ubuntu on it to dual boot with the new Windows 10.

In summary:

My new PC has Windows 10 installed.

I moved my HDD containing an existing Ubuntu installation to the new PC.

I would like to set this up such that I can dual boot with windows 10 and ubuntu. Note, both operating systems are already installed on different HDD's, but the ubuntu installation was installed alongside Windows 7 originally (see extra info below). I just need to make them dual boot together. I can already boot into Ubuntu through my BIOS settings (by making the HDD containing Ubuntu the primary HDD), but I would not like to do that every time.

Extra info:

When I boot from the HDD containing Ubuntu, the grub menu comes on, with Windows 7 still as an option, but I cannot boot into Windows 7 though.

3 Answers 3


You might want to update your grub. There might be somme work to do in the /boot/grub and /dev folders too, since I don't have dual-boot I can't be more of any help :/


I suggest you to to boot into the Ubuntu OS. And then reinstall the GRUB.

I think this command will work for you if are using MBR boot records.

grub-install /dev/sda

where sda is the disk containing Ubuntu.

Depending upon your PC, you might also have option to choose preferred OS by pressing F12 during system startup. But if you want fancy UI, reinstall the GRUB and set its HD as primary boot device


Just run sudo update-grub on ubuntu. It will search for other OSes, delete the windows 7 entry and add the Windows 10 entry. Your ubuntu HDD should be the primary boot entry in bios.

I can also recommend to edit /etc/default/grub, so it contains the following line:


This will automatically select the last booted system as default in the grub menu. After editing this file, you need to run sudo update-grub again. This command will also be executed at kernel updates, so the change would apply after some time anyway.

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