Change Boot Order While Dual Booting

Updated 6 November 2026 · Standard formula, shown below

To change the boot order while dual booting, you need to enter your computer’s firmware settings (BIOS or UEFI) during startup and rearrange the boot device priority list, or use a boot manager menu to select a different OS for the current session. The exact steps depend on your hardware and whether your system uses legacy BIOS or modern UEFI firmware, but the core process is the same across most PCs.

Why Boot Order Matters in Dual Boot

When you install two operating systems on one computer—say, Windows and Linux—the firmware uses a boot order list to decide which OS to load. This list typically includes hard drives, SSDs, USB drives, and network boot options. The first device in the list that contains a valid bootloader gets control. If Windows Boot Manager is listed before your Linux bootloader (like GRUB), the PC will skip the Linux prompt and go straight to Windows. Changing the order lets you decide which OS loads by default, without needing to press a key every time.

How Boot Order Works in UEFI vs. Legacy BIOS

Modern computers use UEFI (Unified Extensible Firmware Interface), which stores boot entries as separate files on a special partition (the EFI System Partition). Each OS has its own bootloader file, and the firmware reads a list of these entries. Legacy BIOS, found on older machines, instead scans the first sector of each drive for a boot signature. In UEFI, you can often reorder individual OS entries directly; in BIOS, you’re limited to ordering whole drives. Most dual-boot systems today use UEFI, so you’ll see entries like “Windows Boot Manager” and “Ubuntu” rather than just drive names.

How to Change the Boot Order

Here are the general steps, which work for most desktops and laptops:

Restart your computer and press the firmware setup key repeatedly as it boots. Common keys are F2, F10, F12, Del, or Esc. The exact key is usually shown briefly on the splash screen or in your manual.
Navigate to the Boot or Startup tab using the arrow keys. On some systems it’s called “Boot Order,” “Boot Priority,” or “Boot Options.”
Look for a list of devices or OS entries. Use the +/– keys, F5/F6, or drag-and-drop with a mouse (if supported) to move your preferred OS’s entry to the top.
Save and exit. Usually this is F10, then confirm with “Yes” or “Save and Reset.”

If you only want to boot a different OS once, without changing the permanent order, use the one-time boot menu (often F12 or F11 during startup) and pick the OS from that list.

Common Problems and Fixes

Several issues can arise when trying to change the boot order:

Can’t find the OS entry: Some firmware only shows drive names, not OS names. In that case, you need to identify which drive holds which OS. You can check from within Windows using Disk Management, or from Linux using lsblk.
Boot order changes don’t stick: This can happen if the firmware resets to defaults after a power loss, or if a CMOS battery is dying. Replace the battery if it’s old.
Windows always boots first despite changes: Windows Update can sometimes rewrite the boot entries and put itself first. You may need to reorder again after a major update.
Secure Boot blocks the other OS: If your Linux distro doesn’t support Secure Boot, you’ll need to disable it in the Security tab, or enable a compatibility mode.

Using a Boot Manager as an Alternative

Instead of fiddling with firmware settings, you can install a boot manager like GRUB (if you’re using Linux) or rEFInd. These programs take over the boot process and present a menu every time you start the PC, letting you choose which OS to load. They also allow you to set a default entry and a timeout. This is often more convenient than changing the firmware order, especially if you switch between OSes frequently. However, a boot manager must be installed correctly, and Windows updates can sometimes overwrite it, so you may need to reinstall it after major updates.

Safety and Precautions

Changing the boot order is generally safe, but there are a few things to keep in mind:

Don’t remove all boot devices: If you set the first device to something that doesn’t have an OS, the PC will show an error like “No bootable device found.” Simply re-enter the firmware and restore the order.
Make sure you know which drive is which: If you have multiple drives, accidentally moving the wrong one to the top could boot a recovery partition or an old OS. Use the drive model numbers in the firmware to match them to your OS.
Back up your data: While changing boot order won’t erase data, a mistake in firmware settings (like disabling a controller) could make your drives inaccessible. A backup is always good practice.

Frequently Asked Questions

How do I change boot order without entering BIOS?

You can use the one-time boot menu (usually F12 or F11) to select a different OS for that session only. To make a permanent change without BIOS, you can use a boot manager like GRUB and edit its configuration file to set a new default OS.

Why does my PC boot straight to Windows and not show GRUB?

This usually means the Windows Boot Manager is first in the boot order, or the Linux bootloader was installed to a partition that isn’t in the list. You can either change the order in firmware, or reinstall GRUB using a live USB and the grub-install command.

Is it safe to change boot order?

Yes, it’s safe as long as you don’t remove all bootable devices. If you make a mistake, you can always re-enter the firmware and change it back. The worst case is a “No bootable device” error, which is easily fixed.

Can I set a different default OS in GRUB?

Yes. In GRUB, edit the /etc/default/grub file and change the GRUB_DEFAULT line to the menu entry number (starting from 0) or the exact name of the OS. Then run sudo update-grub (on Debian/Ubuntu) or the equivalent for your distribution.

Why does the boot order reset after a Windows update?

Windows updates can rewrite the EFI boot entries and sometimes change the order. This is a known issue. You can reorder the entries after the update, or install a boot manager that is more resilient, though it may still be affected.

What if my firmware doesn’t show OS names, only drive names?

That’s common on older BIOS systems. You need to know which physical drive contains which OS. You can check in Windows Disk Management (look for the EFI partition or the system partition) or in Linux with lsblk -f. Then move that drive to the top of the boot order.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.