How to remove Windows from Dual-Boot

Whenever anyone decides to take a dip into the world of Linux, coming from Windows. It's not normally as a straight swap from operating system to operating system. And the distribution you land on using is normally set up in dual-boot.

That's how I got started. Windows paired up with Linux Mint.

"Because I need Windows to play games."

But, with the progress Valve has made with their Proton compatibility layer. I soon realised that I'm never planning on booting Windows up again, and want the storage on my other drive back. So how do we go about removing Windows from a dual-boot system?

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Finding Windows

To find out where Windows is installed on your computer, we can use the fdisk or lsblk command-line utilities.

List partitions using sudo fdisk -l

$ sudo fdisk -l
Disk /dev/nvme0n1: 232.89 GiB, 250059350016 bytes, 488397168 sectors
Disk model: KINGSTON SA2000M8250G
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 098B466C-F305-8C4E-8229-C0882B81A9A6

Device Start End Sectors Size Type
/dev/nvme0n1p1 2048 1128447 1126400 550M EFI System
/dev/nvme0n1p2 1128448 9517055 8388608 4G Linux swap
/dev/nvme0n1p3 9517056 488397134 478880079 228.3G Linux filesystem

Disk /dev/sda: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: Samsung SSD 850
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 8BF1E112-9DF8-42A4-B571-E81529CE4C89

Device Start End Sectors Size Type
/dev/sda1 2048 206847 204800 100M EFI System
/dev/sda2 206848 239615 32768 16M Microsoft reserved
/dev/sda3 239616 975736384 975496769 465.2G Microsoft basic data
/dev/sda4 975736832 976771071 1034240 505M Windows recovery environment

List partitions using lsblk -p

$ lsblk -p
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
/dev/sda 8:0 0 465.8G 0 disk
├─/dev/sda1 8:1 0 100M 0 part
├─/dev/sda2 8:2 0 16M 0 part
├─/dev/sda3 8:3 0 465.2G 0 part
└─/dev/sda4 8:4 0 505M 0 part
/dev/nvme0n1 259:0 0 232.9G 0 disk
├─/dev/nvme0n1p1 259:1 0 550M 0 part
├─/dev/nvme0n1p2 259:2 0 4G 0 part [SWAP]
└─/dev/nvme0n1p3 259:3 0 228.3G 0 part /

fdisk is a more detailed than the simple output from lsblk. Letting us identify the drive that the different Windows partitions are installed on.

So now we know that for this system, Windows is installed on the /dev/sda drive and has four partitions; sda1, sda2, sda3, sda4. We also know from fdisk that the drive has a GPT partition table: Disklabel type: gpt.

Now we can just delete these partitions and replace it with a single Linux Filesystem partition. And format it to match the ext4 type that the rest of this system uses.

IMPORTANT: If you have split a single drive into partitions for both Linux and Windows. As in, partitions for Linux and Windows are both under /dev/sda or /dev/nvme0n1 and not on either drive, like in this tutorial. Make sure to note down the partition numbers for the; Microsoft reserved, Microsoft basic data, and Windows recovery environment partitions. As you will need to keep the EFI System for Linux to use when booting.

Deleting Windows

To delete the partitions on the /dev/sda drive, just pass the path to fdisk. I recommend using fdisk as it's readily available, and allows for ease of mind if you think you might have messed up. As everything you do can be undone by hitting q, as long as you never write the changes with w.

To view all options available, enter m and hit return. For deleting partitions, we're just going to use the d command. And go through the process of deleting each partition.

If you want to check the partitions on the drive first, type p to print out the partition table.

$ sudo fdisk /dev/sda

Command (m for help): d
Partition number (1-4, default 4) 4

Partition 4 has been deleted.

Command (m for help): d
Partition number (1-3, default 3) 3

Partition 3 has been deleted.

Command (m for help): d
Partition number (1,2, default 2) 2

Partition 2 has been deleted.

Command (m for help): d
Selected partition 1
Partition 1 has been deleted.

Creating a partition

Whilst inside of the fdisk utility, we can now create a new partition, using n.

Command (m for help): n
Partition number (1-128, default 1):
First sector (34-976773134, default 2048):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-976773134, default 976773134):

Created a new partition 1 of type 'Linux filesystem' and of size 465.8 GiB.
Partition #1 contains a vfat signature.

Do you want to remove the signature? [Y]es/[N]o: Y

The signature will be removed by a write command.

Here I just hit enter to input all the default values, to get a partition that was as big as my drive could allow.

Also notice how fdisk automatically selected the Linux Filesystem partition type. If you want to change this to another, use l to view all partition type options, and t to change to one.

Just in case you're curious about why the partition defaults to starting at sector 2048 (i.e. 1 MB) I found a good explanation over on StackOverflow

As this drive will be used to store all of my games, I will only keep this single partition. But the same process with n can be repeated to create more if needed.

If in the future I decide that my games library isn't that big or I want to create a video library. I can resize partition /dev/sda1 and create new one along side it.

Writing table changes

After deleting the Windows partitions and creating a new Linux Filesystem partition. This is what the drive will look like when written.

Command (m for help): p
Disk /dev/sda: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: Samsung SSD 850
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 8BF1E112-9DF8-42A4-B571-E81529CE4C89

Device Start End Sectors Size Type
/dev/sda1 2048 976773134 976771087 465.8G Linux filesystem

Filesystem/RAID signature on partition 1 will be wiped.

To commit these changes and write the table to disk and exit, type in w and hit enter.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

Formatting the partition

To activate this new partition to be used on my system. I need to format this new partition to be of the same type, ext4, by entering the command sudo mkfs.ext4 /dev/sda1.

$ sudo mkfs.ext4 /dev/sda1
mke2fs 1.46.4 (18-Aug-2021)
Discarding device blocks: done
Creating filesystem with 122096385 4k blocks and 30531584 inodes
Filesystem UUID: 4149ff1e-bd86-4d4f-940f-c79cc910ded0
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000

Allocating group tables: done
Writing inode tables: done
Creating journal (262144 blocks): done
Writing superblocks and filesystem accounting information: done

Mounting the new partition

Once formatted, the drive partition needs to be mounted, and stay mounted every time the system is booted. To do that, we need to decide where to permanently mount this partition.

Where to mount the partition

A common directory mentioned is in a /media directory. But this is usually associated with removable media, so would be more suitable for my USB devices and CDs.

Typically, the /mnt directory is given as such a place. However, this is typically only meant for temporary mounts of storage devices. And if there are any drives already mounted in sub-directories of /mnt, then they will be hidden whilst a drive is mounted to /mnt.

The most practical option I use as there is no standard place set out for permanent secondary drives, is in a sub-directory of /mnt. For example, /mnt/games. So lets create a new directory there.

$ sudo mkdir -p /mnt/games/

The -p flag options refers to --parents, which will make sure to create all parent directories to games/. Although /mnt should be there anyway.

Automatically mount on boot

To make sure the system mounts the drive partition /dev/sda1 in /mnt/games/ on every boot. Edit the /etc/fstab file, which will already contain your current partitions. Using the UUID of the partition, found with the lsblk -f command.

$ sudo /etc/fstab

# Static information about the filesystems.
# See fstab(5) for details.

# <file system> <dir> <type> <options> <dump> <pass>
# /dev/nvme0n1p3
UUID=05ed8f02-f092-40e5-b72b-38cacce9b370 / ext4 rw,relatime 0 1

# /dev/nvme0n1p2
UUID=9a54cd9a-c6af-403a-a32a-cc08c0adc60b none swap defaults 0 0

# /dev/sda1
UUID=4149ff1e-bd86-4d4f-940f-c79cc910ded0 /mnt/games ext4 defaults 0 2

Only the bottom two lines were added to this file.

What we did: - Used the default of using the file system UUIDs to denote the partition identity. - Assigned the mount point directory /mnt/games. - Given the default options for the partition. - Kept dump as 0 to stop automatically backing up the entire drive if you use dump (not always pre-installed). - Given a pass priority of 2, as the root directory should be checked first at boot time.

Mount without rebooting

Once the changes have been saved, we can run sudo mount /mnt/sda1 without having to reboot the computer yet. This will check the /etc/fstab file and use it to know to mount /dev/sda1/ at /mnt/games.

Now if we run lsblk command, under MOUNTPOINTS the file system will be mounted to the correct directory. Meaning that whenever the system is next booted, it will automatically mount to this point.

$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 465.8G 0 disk
└─sda1 8:1 0 465.8G 0 part /mnt/games
nvme0n1 259:0 0 232.9G 0 disk
├─nvme0n1p1 259:1 0 550M 0 part
├─nvme0n1p2 259:2 0 4G 0 part [SWAP]
└─nvme0n1p3 259:3 0 228.3G 0 part /

Giving user privileges

This new file system is still only accessible to the root user, being in the root / directory. To change this, run the following sudo chown -R richard:users /mnt/games.

Updating GRUB

At this point we have now removed Windows from the system. The Boot manager, Grub, will now need to be updated. To display the currently installed operating systems on your computer.

$ sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/initramfs-linux.img
Found fallback initrd image(s) in /boot: initramfs-linux-fallback.img
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Adding boot menu entry for UEFI Firmware Settings ...
done

Now when you next restart your system, Windows will no longer be an option in the boot menu.

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If you've made it this far, thanks for reading!

I hope this article has been helpful in understanding some of the utilities found on Linux, such as fdisk and lsblk. And that you now understand the file system of your own machine bit better too.

If you've got any questions about this process, or think I might have missed something, just ask below.

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Originally published on xhalford.com