In this post we will discuss the process of how to install Ubuntu on a System that already have Windows Preinstalled.

Note*: Even if you are starting from a blank Hard drive it is always advised to install Windows first before installing Ubuntu.

I prefer to install Linux in dual boot with Windows. I hardly use Windows but it gives me sort of back up if I mess up with things. Dual-booting Linux with Windows is always suggestible for beginners. In this post, we shall see how to install Ubuntu in dual boot mode with Windows.

The steps mentioned here are applicable to other Ubuntu-based Flavors or Linux distributions such as Linux Mint, Elementary OS etc. 

Dual boot Ubuntu with Windows 10 and Windows 8.1:

Though I have used Ubuntu 20.04 here, it is applicable to all versions of Ubuntu, be it Ubuntu 18.04 or Ubuntu 20.10. There are various prerequisites to install Ubuntu on a UEFI system. I’ll list them for easier read here:

  • Ubuntu ISO burned to a USB or DVD (we’ll see it)
  • Windows backup (optional)
  • Windows 10 bootable USB (optional yet recommended as it will save your day if anything goes wrong)

Step 1: Make a backup [optional]

It is always nice to make a backup, just in case if you mess up with the system. There are numerous articles on the web to show you how to back up your system. 

Step 2: Create a live USB/disk of Ubuntu

The next thing you need to do is to create a live USB or disk. I recommend Rufus to create a live USB of Linux OS in Windows. You can use the instructions here to create the USB.

Step 3: Make a partition where Ubuntu will be installed

Assuming tat you have a fresh system, the first thing we need to do is to make a partition to install Linux. The 256 GB in my system was already had several partitions from manufacturer but mainly for backup and other purposes. Main partition was C drive, of around 220 GB, where Windows 8.1 was installed.

If you have just one partition like this, you need to make some free space out of it for Linux. If you have several partitions of considerable size, use any of them except C drive because it may erase the data.

To make a partition in Windows 8, go to Disk Management tool. You can find disk management tool by searching for ‘disk’ in Control Panel.

In the Disk Management tool, right click on the drive which you want to partition and select shrink volume. In my case, I shrank the C drive to make some free space:

You can leave the free space as it is. We shall use it while installing Ubuntu.

Step 4: Disable fast startup in Windows [optional]

Windows 8 introduced a new feature called “fast startup” for quick boot. While it is not mandatory, it would be better to have it disabled.

Go to Control Panel > Hardware and Sound > Power Options > System Settings > Choose what the power buttons do and uncheck the Turn on fast startup box.

Step 5: Disable secureboot in Windows 10 and 8.1

This is the most important step. The new secure boot feature of Windows 8, originally intended for security feature for rootkit viruses, prevents dual booting of Windows with Linux. To dual boot Windows 8 with Linux, we must disable secure boot in UEFI.

Step 6: Installing Ubuntu along with Windows 10, 8.1

Once you have disabled secure boot, it’s time to install Ubuntu. I hope you already created the live USB as mentioned in step 2. Plug in the USB and boot the system from it.

To boot from USB, will have to choose boot from USB option from within Windows itself. Either with PC Setting (like for UEFI) or pressing shift key while clicking on Restart.

Once you have booted in the live USB, you will be presented with option to try or install Ubuntu. Click on install. You will be presented with few screen options to choose the language. It will then do some checks on available space, power and internet connection etc. Just click on Continue.

Note*: On the Following screen “Installation Type” you might have the option to install alongside Windows. That is usually the best option. Some of the Ubuntu Distributions do not give you that option so follow the next steps.

The main screen which you should pay attention to is Installation Type. Choose Something else here:

Remember we had created some free space beforehand? We shall use the free space to create Root, Swap and Home. Select the free space and click on the + sign.

It will provide you with option to create Linux partition. We are creating the Root partition. Any thing above 20 GB is more than sufficient for it. Choose the size, select Ext 4 as file type and / (means root) as the mount point.

Clicking on OK in previous step will bring you to the partition screen. Next we will create swap. Like previously, click on the + sign again. This time use the file type as Swap area. Suggestible swap size is double of RAM.

In similar fashion, create a Home partition. Allocate it maximum space (in fact allocate it rest of the free space) because this is where you’ll save music, pictures and downloaded files.

Once you are ready with Root, Swap and Home, click on Install Now:

Well, you have almost won the battle. You can smell victory now. Next you will be asked to set username password etc. Basically, you just need to click next now.

Once the installation is completed, restart the computer, you should be welcomed by a purple grub screen. Enjoy Ubuntu along with Windows 10 in dual boot mode.