Set Your Computer to Boot from a USB Flash Drive [Windows & macOS]

Knowing how to boot your computer from a USB flash drive is an essential skill for every computer user. Whether you want to install a fresh copy of Windows, troubleshoot startup problems, run a recovery tool, or install another operating system, changing the boot device allows your computer to start from the USB drive instead of the internal storage.

Many beginners think changing the boot order is complicated, but it is actually a straightforward process once you understand the basic steps. The exact menus may look slightly different depending on your computer manufacturer, but the overall process remains very similar. 

In this guide, I will explain everything in simple language, making it easy even if you have never entered the BIOS, UEFI, or Startup Manager before.

Set Your Computer to Boot from a USB Flash Drive [Windows]

Before you begin, make sure your USB flash drive is bootable. A regular USB drive containing files will not work. You must first create a bootable USB using a trusted tool such as the Windows Media Creation Tool, Rufus, or another operating system installer.

Step 1: Connect the Bootable USB Flash Drive

Insert the bootable USB flash drive into one of your computer’s USB ports before turning on the computer. Using a USB port directly on the computer is recommended instead of using a USB hub because the system can detect the drive more reliably during startup.

If your computer has both USB 2.0 and USB 3.0 ports, either should work on most modern computers. However, if the USB drive is not detected during startup, try another USB port before assuming there is a problem with the flash drive.

Step 2: Completely Shut Down Your Computer

Save any open work and perform a complete shutdown instead of simply restarting from Sleep or Hibernate mode. A full shutdown ensures your computer performs a fresh hardware check during startup, allowing it to detect the bootable USB drive.

Wait several seconds after the computer powers off before continuing to the next step.

Step 3: Open the Boot Menu or BIOS Settings

Turn on the computer and immediately begin pressing the appropriate keyboard key. Different manufacturers use different keys.

Common keys include F2, F10, F12, Esc, Delete, and occasionally F11. Some laptops briefly display a message such as “Press F12 for Boot Menu” or “Press DEL to Enter Setup” during startup.

If you enter the Boot Menu, you can temporarily choose the USB drive without permanently changing the boot order.

If you enter the BIOS or UEFI Setup Utility, you will need to adjust the boot priority manually.

If Windows starts normally, restart the computer and try pressing the key again earlier during startup.

Step 4: Locate the Boot Settings

Inside the BIOS or UEFI interface, look for a section named Boot, Boot Options, Startup, Boot Configuration, or something similar.

Modern UEFI interfaces often include mouse support, while older BIOS screens require you to use the keyboard arrow keys to navigate. Read the instructions displayed on the screen carefully because they explain which keys allow you to move, select, save, and exit.

Take your time while navigating the menus. There is no need to rush because changing only the boot settings will not affect your personal files.

Step 5: Select the USB Flash Drive as the First Boot Device

Locate the Boot Priority or Boot Order list.

Find your USB flash drive in the list of available devices. It may appear under its manufacturer name, such as SanDisk, Kingston, Samsung, or as UEFI USB Device.

Move the USB drive to the top of the boot priority list. This tells the computer to check the USB drive first whenever it starts.

If you are using the one-time Boot Menu instead of BIOS, simply highlight the USB drive and press Enter.

Step 6: Save the Changes

After selecting the correct boot order, save your settings.

Most BIOS systems use the F10 key to save and exit, although some computers use a different key. You can also choose the Save and Exit option from the menu.

The computer will restart automatically after saving your changes.

Step 7: Boot from the USB Flash Drive

As the computer starts again, it should detect the bootable USB drive and load its installation or recovery environment instead of Windows.

Depending on the contents of the USB drive, you may see the Windows Setup screen, a Linux installer, a recovery utility, or another operating system installer.

If Windows starts normally instead, restart the computer and verify that the USB drive is bootable and still appears first in the boot order.

Step 8: Restore the Original Boot Order After Finishing

After installing Windows or completing your recovery task, remove the USB flash drive and restart the computer.

If you permanently changed the boot order in BIOS, you may wish to place your internal SSD or hard drive back at the top of the boot priority list. This allows the computer to start Windows normally without checking the USB drive every time it powers on.

Set Your Computer to Boot from a USB Flash Drive [macOS]

Mac computers handle USB booting differently than Windows computers. Instead of using a traditional BIOS or UEFI interface, most Macs use Startup Manager to let you choose which drive to boot from.

The steps vary slightly depending on whether your Mac has an Intel processor or Apple Silicon.

Step 1: Prepare a Bootable USB Drive

Create a bootable macOS installer or another compatible bootable USB drive before starting.

Make sure the installer was created correctly. An improperly prepared USB drive will not appear in Startup Manager.

Connect the USB drive directly to the Mac before powering it on.

Step 2: Turn Off the Mac Completely

Close all applications and choose Shut Down from the Apple menu.

Wait until the display is completely black and you no longer hear any system activity before proceeding.

A complete shutdown ensures the Mac performs a fresh startup sequence.

Step 3: Open Startup Manager

For an Intel Mac, press the power button and immediately hold the Option key until the Startup Manager appears.

For a Mac with Apple Silicon, press and hold the power button. Keep holding it until the Startup Options screen appears.

After a few moments, the available startup disks will appear on the screen.

Step 4: Select the USB Flash Drive

Locate the bootable USB drive among the available startup disks.

Click or highlight the USB drive and continue with the startup process.

If the USB drive does not appear, disconnect it, reconnect it, and restart the Mac before trying again.

Step 5: Continue Booting from the USB Drive

After selecting the USB installer, the Mac begins loading directly from the flash drive.

This process may take several minutes depending on your Mac model and the speed of the USB drive.

Once loading is complete, you can install macOS, access recovery utilities, repair the startup disk, or perform other maintenance tasks.

Step 6: Choose the Startup Disk After Installation

When you finish installing macOS or using the recovery tools, restart your Mac.

If you want the internal storage to become the default startup device again, open System Settings, select General, choose Startup Disk, and select your internal drive.

Restart the Mac once more to confirm it starts normally.

FAQs

Why is my USB flash drive not showing in the Boot Menu?

The USB drive may not be bootable, may not be connected properly, or Secure Boot settings may prevent it from appearing. Recreating the bootable USB and trying another USB port often solves the problem.

What is the difference between BIOS and UEFI?

BIOS is the older firmware used on computers, while UEFI is its modern replacement. Both allow you to configure hardware settings and choose which device your computer starts from.

Can I boot Windows from any USB flash drive?

No. The USB flash drive must contain a properly created bootable installer or operating system. Simply copying Windows files onto a USB drive will not make it bootable.

Will changing the boot order delete my files?

No. Changing the boot order only tells the computer which device to check first during startup. It does not erase data from your computer or your USB drive.

Do I need to change the boot order every time?

No. If your computer has a Boot Menu, you can simply choose the USB drive for one startup without permanently changing the boot order.

Can all Macs boot from a USB drive?

Most Intel-based Macs and Apple Silicon Macs support booting from compatible USB installers. However, the installer must be properly created and supported by your Mac model.

Summary

Booting from a USB flash drive is useful for installing a new operating system, repairing startup problems, recovering important files, and performing advanced maintenance. 

Although Windows and macOS use different startup methods, both make it possible to launch your computer from a properly prepared USB drive.

For Windows computers, you generally access the Boot Menu or BIOS/UEFI settings to select the USB device. On a Mac, you use Startup Manager to choose the bootable USB during startup. 

Once you understand these simple steps, you can confidently boot from a USB flash drive whenever you need to install software, troubleshoot problems, or recover your system.