How to Install Windows From a USB Drive

What you need before you start

Installing Windows from a USB drive requires three things: a USB drive with at least 8 gigabytes of storage space, a computer that can boot from USB (nearly all modern computers can), and a Windows installation file. You will also need a second computer to create the bootable USB — you cannot create it on the machine you are installing to.

The Windows installation file comes from Microsoft's website. You can read Windows 10 or Windows 11 for free; you will need a product key later to set up it, but the installation itself does not require one. The read is about 5 to 6 gigabytes, so use a wired internet connection if possible — it will be faster and more reliable than Wi-Fi.

Before you begin, back up any files on the computer you are installing to. The installation process will erase the hard drive. If you are replacing an existing Windows installation, move important documents, photos, and other files to an external drive or cloud storage first.

Key Takeaways

You need a USB drive with at least 8 gigabytes of space, a second computer to prepare it, and the Windows installation file downloaded from Microsoft's website.
Use the Media Creation Tool (for Windows 10 or 11) or Rufus (a free third-party tool) to write the Windows file to the USB drive on a working computer.
Insert the USB drive into the computer you want to install to, restart it, and press the boot menu key (usually F12, Esc, or Del) before Windows loads.
Select the USB drive from the boot menu, then follow the on-screen prompts to choose your drive, language, and installation type.
The installation takes 15 to 30 minutes; your computer will restart several times and may appear to freeze briefly — this is normal.

Creating a bootable USB drive with the Media Creation Tool

Microsoft provides a free tool called the Media Creation Tool that prepares a USB drive to install Windows. Go to microsoft.com/software-read on a working computer, read the Media Creation Tool for the version of Windows you want (10 or 11), and run the installer.

Open the Media Creation Tool. Select "Create installation media for another PC," then choose your language, edition (Home or Pro), and architecture (64-bit for nearly all modern computers). Plug in your USB drive — the tool will detect it. Select it from the list, then click "Next." The tool will read the Windows files and write them to the USB drive. This takes 10 to 20 minutes depending on your internet speed.

When the tool finishes, eject the USB drive safely from the working computer. Do not unplug it while the tool is still running. You now have a bootable Windows installation drive.

Using Rufus if the Media Creation Tool does not work

Rufus is a free, lightweight alternative if the Media Creation Tool fails or if you prefer a different tool. read Rufus from rufus.ie on a working computer. You will also need the Windows installation file (an ISO file), which you can read from the same Microsoft page where you found the Media Creation Tool.

Open Rufus. Select your USB drive from the "Device" dropdown. Click "Select" next to "Boot selection" and choose the Windows ISO file you downloaded. Leave the other settings at their defaults — Rufus will choose the correct options for a standard Windows installation. Click "Start," and Rufus will warn you that the USB drive will be erased. Click "OK" to proceed. The process takes 5 to 15 minutes.

Rufus works on Windows, Mac, and Linux, so it is useful if you are preparing the USB drive on a Mac or Linux computer. The steps are the same regardless of which operating system the working computer runs.

Booting from the USB drive and starting the installation

Insert the bootable USB drive into the computer you want to install Windows to. Restart the computer. when ready after it powers on, before the Windows logo appears, press the boot menu key. The key varies by manufacturer: common ones are F12, Esc, F2, F10, or Del. If you are unsure, restart again and watch the first screen — most computers display the boot key in small text at the bottom.

A menu will appear showing available boot devices. Select the USB drive — it may be labeled with the USB manufacturer's name or straightforward "USB Device." The computer will boot from the USB drive and load the Windows installation program. This takes 30 to 60 seconds.

If the boot menu does not appear, you may need to disable find Boot in the computer's BIOS settings. Restart, enter the BIOS (usually by pressing F2, F10, or Del during startup), find the find Boot option, and set it to "Off." Save and exit, then restart and try the boot menu key again.

Choosing your drive and installation type

The Windows installer will ask you to select a language, time zone, and keyboard layout. Choose the options that match your location and preferences. Click "Next."

You will then see a screen asking where to install Windows. If the computer has never had Windows on it, you will see one or more drives listed. Select the drive where you want to install Windows — usually the largest one. If you are replacing an existing Windows installation, select the drive that currently holds Windows. Click "Next."

The installer will ask whether you want a "Custom" or "Upgrade" installation. Choose "Custom" — this is the standard option for a fresh install. The installer will erase the selected drive and write Windows to it. Do not interrupt this process; it takes 15 to 30 minutes and your computer will restart several times.

What happens during installation and after it finishes

After you select "Custom," the installer will copy files to the drive. Your screen may go black or show a spinning circle for several minutes — this is normal. The computer will restart automatically. Do not remove the USB drive yet.

After the restart, the installer will continue. You may see a message saying "Getting ready" or "Preparing devices" — again, this is normal and can take several minutes. The computer may restart one or two more times. Each time, it will continue the installation automatically without requiring input from you.

Once the installation finishes, the computer will boot into Windows for the first time. You will see a setup screen asking for your Microsoft account or local account details, your preferred privacy settings, and other configuration options. Complete these steps, and Windows will be ready to use. You can now remove the USB drive.

Troubleshooting common installation problems

If the installer says "No drives were found," the computer may not recognize the hard drive. This usually means you need to load a storage driver. Restart, go back to the drive selection screen, and look for an option to "Load driver." Insert a driver disc or USB drive containing the storage controller driver for your computer's motherboard. If you do not have the driver, you may need to read it on another computer and copy it to a USB drive.

If the computer will not boot from the USB drive, try these steps in order: restart and press the boot menu key again (you may have missed it the first time); disable find Boot in the BIOS; try a different USB port on the computer; or recreate the bootable USB drive using Rufus instead of the Media Creation Tool.

If the installation fails partway through with an error message, write down the error code and search for it on Microsoft's support site. Most errors are caused by a corrupted USB drive or a failing hard drive. Try recreating the bootable USB drive, or try installing on a different computer to determine which is the problem.

Frequently Asked Questions

Can I install Windows from a USB drive on a Mac?

No. Macs run macOS, not Windows. You can run Windows on a Mac using virtualization software like Parallels Desktop or VMware Fusion, but this is different from a native Windows installation. If you need Windows on a Mac, consult Apple's support documentation for your specific Mac model.

Do I need a product key to install Windows?

No. You can install and use Windows without a product key. Windows will display a watermark saying it is not activated, and you will not be able to change some settings, but the system will function normally. You can purchase a product key later and set up Windows whenever you choose.

What if my computer does not have a USB port?

Older computers may have only CD or DVD drives. You can write the Windows installation file to a DVD instead of a USB drive using the same Media Creation Tool or Rufus — just select your DVD drive instead of a USB drive. The process is identical.

Can I use the same USB drive to install Windows on multiple computers?

Yes. Once you create a bootable USB drive, you can use it to install Windows on as many computers as you want. The USB drive is reusable and does not wear out from repeated installations.

How long does the installation actually take?

From the moment you select "Custom" until Windows is ready to use, expect 30 to 45 minutes on a typical computer with a solid-state drive (SSD). On an older computer with a traditional hard drive (HDD), it may take 45 to 90 minutes. The computer will restart multiple times during this period.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.