How to Set Up Dual Boot: Windows 11 and Linux on One PC

Jul 11, 2009

Updated • Nov 8, 2026

Linux

To set up dual boot, install Windows first, back up your data, turn off BitLocker and Fast Startup, then shrink the Windows partition to free at least 25 GB. Write a Linux installer such as Ubuntu to a USB drive, boot from it in the same UEFI mode as Windows, and choose the installer option that installs alongside Windows. The GRUB boot menu then lets you pick an operating system at every start.

This guide uses Windows 11 and Ubuntu as the example pair because that is the most common dual boot setup, but the same checks apply to Linux Mint, Fedora and other distributions. It covers the preparation that decides whether the install works, the installation itself, and what to do when Windows does not show up in the boot menu.

What dual boot means and what you need

Dual boot means two operating systems are installed on one computer, each on its own partition or drive, and a boot menu lets you choose which one starts. Only one system runs at a time; nothing is emulated, so both get full access to the hardware. Ubuntu's own desktop installation tutorial lists the basics:

A PC with at least 25 GB of free storage for Ubuntu (more if you plan to install many apps or keep files there).
A USB flash drive of 12 GB or more; it is erased when the installer is written to it.
A full backup of your Windows files on an external drive or cloud storage.
Your BitLocker recovery key, saved somewhere outside the PC, if the drive is encrypted.
The Linux ISO image downloaded from the distribution's official site.

If your PC has a second internal drive, installing Linux on that drive is the cleanest option: no Windows partition needs to be resized and each system keeps its own disk. An external SSD also works; see our guide on installing Linux on an external SSD.

Prepare Windows before you install Linux

Preparing Windows is the step that decides whether a dual boot install succeeds, because most failures come from encryption, storage drivers or a half-shut-down Windows partition. Install Windows first if the PC is new or empty: Ubuntu's community documentation recommends this order, because the Windows installer does not add Linux to its boot menu, while the Ubuntu installer detects Windows. Then work through these checks:

Back up everything. Partition changes are safe in normal use, but a wrong click in the installer can erase a drive.
Turn off BitLocker. Save your BitLocker recovery key outside the PC first (a Microsoft account, a USB stick or a printout), then open Settings, search for "Manage BitLocker", and turn it off for the system drive. Decryption takes a while. Ubuntu notes that on PCs where BitLocker is enabled but not yet encrypted, you must turn it on and then off before the installer can read the drive.
Turn off Fast Startup. Search for "Choose a power plan", select "Choose what the power button does", click "Change settings that are currently unavailable", clear "Turn on fast startup" and click "Save changes". Fast Startup leaves the Windows partition in a hibernated state that Linux should not write to.
Check the boot mode. Run msinfo32 and look at "BIOS Mode". Windows 11 PCs normally show UEFI, and Linux must be installed in the same mode.
Check the storage controller. If the firmware uses Intel Rapid Storage Technology (RST), Ubuntu's installer stops with an alert; Ubuntu does not support RST and asks you to switch the controller setting in the firmware first.

If you want BitLocker back on the Windows drive later, check first: Ubuntu warns that some Windows editions do not allow re-enabling it after it has been turned off. Our guide on stopping Windows 11 from encrypting drives during installation explains why many new PCs ship with encryption already active.

Shrink the Windows partition to make room

Shrinking the Windows partition creates the unallocated space that Linux installs into, and Windows' own Disk Management tool does it without third-party software. Right-click the Start button, open Disk Management, right-click the C: volume and choose "Shrink Volume". Enter the amount of space to free in MB (for example 102400 for 100 GB) and confirm. Leave the new space unallocated; the Linux installer formats it.

Microsoft documents one common limit: files that cannot be moved, such as the paging file or shadow copy storage, set a floor below which the volume cannot shrink. If Disk Management offers less space than you expect, you can temporarily move the paging file or delete stored shadow copies, shrink again, and then restore the paging file. Event ID 259 in the Application log names the file that blocked the shrink. You can also skip this step entirely and let the Ubuntu installer resize Windows with its built-in slider, but shrinking in Windows first lets Windows check its own file system.

Create the bootable USB and start the installer

A bootable USB drive holds the Linux installer, and the PC starts from it instead of the internal drive. Ubuntu's tutorial uses balenaEtcher: install it, select the downloaded ISO, select the USB stick and click "Flash!". Copying the ISO file onto the stick does not work; it must be written as an image.

To start from the stick, plug it in and restart. Press the boot menu key while the manufacturer logo shows: F12 is the most common, with Esc, F2 and F10 used by some brands. Choose the USB entry that is labelled UEFI, which keeps the installer in the same mode as Windows. Ubuntu's UEFI documentation is clear that if Windows boots in UEFI mode, Ubuntu must be installed in UEFI mode too. Secure Boot can stay on: all current 64-bit Ubuntu releases support it. If the stick does not boot with Secure Boot enabled, disabling it in the firmware is Ubuntu's suggested workaround.

If you also need a fresh Windows installer, create one with the Windows 11 Media Creation Tool.

Install Linux alongside Windows

The Ubuntu installer offers a dedicated option for dual boot, and choosing it is the main decision during setup. After language, keyboard and network screens, the disk setup screen shows these choices (exact labels vary slightly between releases):

Installer option	What it does	Use it when
Install Ubuntu alongside Windows	Keeps Windows and gives Ubuntu space set with a slider	Normal dual boot on one drive
Manual partitioning	You create and assign partitions yourself	A second drive, or a custom layout
Erase disk and install Ubuntu	Deletes everything on the selected drive	Never for dual boot on the Windows drive

If you prepared unallocated space or a second drive, select it and finish the remaining screens (user account, time zone). Under "Advanced features" you can encrypt the new Ubuntu installation. When the installer asks, remove the USB stick and restart. The GRUB menu appears, with Ubuntu listed first and Windows Boot Manager below it; GRUB boots the top entry automatically after a short countdown.

Fix common dual boot problems

Most dual boot problems after installation come from the firmware boot order or from Windows changing the disk state, and each has a direct fix:

The PC boots straight into Windows: open the firmware settings and move the Ubuntu entry above Windows Boot Manager in the boot order, or use the one-time boot menu key.
The installer does not offer to install alongside Windows: BitLocker is still on, Intel RST is active, or the USB stick started in legacy mode instead of UEFI.
Windows is missing from GRUB: confirm both systems use UEFI mode, then boot Linux and run sudo update-grub. GRUB 2.06 and later disable os-prober by default, so on some releases you must first add GRUB_DISABLE_OS_PROBER=false to /etc/default/grub.
Windows asks for a BitLocker recovery key: enter the key you saved before the install. Boot changes can trigger this prompt.
Wi-Fi or hardware does not work in Linux: install the missing drivers through the distribution's driver tool; our guide to getting Wi-Fi working in Linux Mint after installation covers a typical case.

To remove Linux later, delete its partitions in Windows Disk Management, extend the Windows volume into the freed space, and set Windows Boot Manager as the first boot entry in the firmware.

FAQ

Does dual booting slow down my computer?

No. Only one operating system runs at a time, so performance is the same as a single install. The only costs are disk space and the few seconds the boot menu waits.

Can I dual boot two versions of Windows?

Yes. Shrink the existing partition, install the second Windows into the free space from a Windows installer USB, and Windows Boot Manager lists both versions automatically.

Can Windows and Linux share files in a dual boot setup?

Yes. Linux can read and write NTFS partitions, so it can open your Windows files once Fast Startup is off. Windows cannot read Linux ext4 partitions without extra software, so a shared NTFS data partition is the simplest option.