How to Dual Boot Windows 10 and Linux

Dual booting Windows 10 and Linux gives you the best of both worlds—Windows for gaming and general-purpose applications, and Linux for development, system administration, or open-source tooling. However, managing two operating systems on a single machine is a delicate operation that requires precision and planning.

This advanced guide walks you through the steps of setting up a clean and efficient dual-boot system using UEFI, GPT, and modern Linux distributions such as Ubuntu, Fedora, or Arch Linux.

Step 1: Prepare the Disk for Dual Booting

Option A: Windows Already Installed

1. Shrink the Windows partition:

• Go to Disk Management → Right-click the main partition (usually C:) → Shrink Volume.
• Leave at least 50 GB of unallocated space for Linux.

1. Disable Fast Startup & BitLocker:

• Control Panel → Power Options → Choose what power buttons do → Turn off Fast Startup.
• Ensure BitLocker is turned off on system drives (Control Panel > BitLocker).

1. Check EFI Partition:

   • Ensure you have an EFI System Partition (~100–500 MB, FAT32).

   • You can verify this using:

     diskpart
list disk
select disk 0
list partition


 Step 2: Create Linux Installation Media

1. Download your preferred Linux distro (e.g., Ubuntu LTS, Fedora Workstation).

2. Use Rufus or dd (on Linux/macOS) to create a bootable USB.

   sudo dd if=linux.iso of=/dev/sdX bs=4M status=progress && sync


3. Boot from the USB:

• Enter UEFI/BIOS settings → Disable Secure Boot (optional for some distros).
• Set the USB drive as first boot device.

Step 3: Install Linux Alongside Windows

1. Boot into Live Linux environment and start the installer.

2. Manual partitioning:

   • Use Something Else (Ubuntu) or Custom Partitioning option.

   • Identify the unallocated space.

   • Create the following partitions:

     • / (root): ext4, 30–60 GB

     • [Optional] /home: ext4, separate user data

     • [Optional] swap: 2–4 GB or based on RAM if you want hibernation

3. Set EFI partition:

   • Do not format the EFI System Partition (ESP).

   • Mount it as /boot/efi.

4. GRUB Bootloader:

   • Choose to install GRUB on the EFI partition (not MBR).

   • Typically ESP is /dev/sda1 or /dev/nvme0n1p1.

5. Finish installation and reboot.

Step 4: Configure UEFI Boot Order

After installation, the system may still boot directly into Windows. Here’s how to ensure GRUB appears:

1. Access UEFI firmware:

   • Hit F2, DEL,  ESC, or another key (depends on manufacturer).

2. Change Boot Order:

   • Set “ubuntu” or “Linux Boot Manager” above “Windows Boot Manager.”

3. Using Windows Command Line:

   bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi


Or install and use efibootmgr on Linux to reorder boot entries:

Optional Post-Install Steps

1. GRUB Customization

• Use tools like grub-customizer or manually edit /etc/default/grub:

  GRUB_TIMEOUT=5


  GRUB_DEFAULT=0


  GRUB_DISTRIBUTOR=`lsb_release -i -s`


2. Update GRUB after any config changes:

3. Re-enable Secure Boot (Optional)

If your Linux distribution supports signed bootloaders (e.g., Ubuntu), you may re-enable Secure Boot after installation.

Conclusion

Dual-booting Windows 10 and Linux is a powerful setup, offering flexibility and freedom. While the process may seem intricate, especially with UEFI and GPT partitioning, a methodical approach ensures a clean, recoverable installation. Always back up your data, double-check partition targets, and keep a live USB handy for recovery or GRUB repair.

With proper setup, you’ll enjoy a robust dual-boot system ready for development, gaming, and everything in between.