Install Windows from a USB Flash Drive

Here’s how to create a bootable Windows installation USB drive starting with a Windows .iso file or a Windows Setup DVD.

If you’re looking for an easy way to create a bootable USB Windows installation drive, use the media creation tool.

What you need

• Windows 10 install .iso or DVD
• USB flash drive with at least 5GB free space. This drive will be formatted, so make sure it doesn’t have any important files on it.
• Technician PC — Windows PC that you’ll use to format the USB flash drive
• Destination PC — A PC that you’ll install Windows on

Step 1 — Format the drive and set the primary partition as active

Connect the USB flash drive to your technician PC.

Open Disk Management: Right-click on Start and choose Disk Management.

Format the partition: Right-click the USB drive partition and choose Format. Select the FAT32 file system to be able to boot either BIOS-based or UEFI-based PCs.

Set the partition as active: Right-click the USB drive partition and click Mark Partition as Active.

If Mark Partition as Active isn’t available, you can instead use diskpart to select the partition and mark it active.

Step 2 — Copy Windows Setup to the USB flash drive

Use File Explorer to copy and paste the entire contents of the Windows product DVD or ISO to the USB flash drive.

Optional: add an unattend file to automate the installation process. For more information, see Automate Windows Setup.

Step 3 — Install Windows to the new PC

Connect the USB flash drive to a new PC.

Turn on the PC and press the key that opens the boot-device selection menu for the computer, such as the Esc/F10/F12 keys. Select the option that boots the PC from the USB flash drive.

Windows Setup starts. Follow the instructions to install Windows.

Remove the USB flash drive.

If your Windows image is larger than 4GB

Windows USB install drives are formatted as FAT32, which has a 4GB filesize limit. If your image is larger than the filesize limit:

Copy everything except the Windows image file (sources\install.wim) to the USB drive (either drag and drop, or use this command, where D: is the mounted ISO and E: is the USB flash drive.)

Split the Windows image file into smaller files, and put the smaller files onto the USB drive:

How to Boot From a USB Device

Make your PC boot from a USB flash drive or external hard drive

There are lots of reasons you might want to boot from a USB device, like an external hard drive or a flash drive, but it’s usually so you can run special kinds of software.

When you boot from a USB device, what you’re doing is running your computer with the operating system installed on the USB device. When you start your computer normally, you’re running it with the operating system installed on your internal hard drive—Windows, Linux, etc.

Time Required: Booting from a USB device usually takes 10–20 minutes, but it depends a lot on if you have to make changes to how your computer starts up.

How to Boot From a USB Device

Follow these easy steps to boot from a flash drive, an external hard drive, or some other bootable USB device.

If the USB boot option is not first in the boot order, your PC will start «normally» (i.e., boot from your hard drive) without even looking at any boot information that might be on your USB device.

The BIOS on most computers lists the USB boot option as USB or Removable Devices, but some confusingly list it as a Hard Drive option, so be sure to dig around if you’re having trouble finding the right one to choose.

After setting your USB device as the first boot device, your computer will check it for boot information each time your computer starts. Leaving your computer configured this way shouldn’t cause problems unless you plan on leaving the bootable USB device attached all the time.

Attach the USB device to your computer via any available USB port.

Creating a bootable flash drive or configuring an external hard drive as bootable is a task in itself. Chances are you made it to these instructions here because you know whatever USB device you have should be bootable after properly configuring BIOS.

See our How to Burn an ISO File to a USB Drive tutorial for general instructions on doing exactly that, which tends to be the reason most people need to figure out how to boot from one.

Since you’re not actually inside of the operating system at this point, restarting isn’t the same as using normal restart buttons. Instead, BIOS should explain which key to press—such as F10—to save the boot order changes and restart the computer.

Watch for a Press any key to boot from external device. message.

You may be prompted with a message to press a key on some bootable devices before the computer boots from the flash drive or another USB device.

If this happens, and you do nothing, your computer will check for boot information on the next boot device in the list in BIOS (see Step 1), which will probably be your hard drive.

Most of the time, when trying to boot from a USB device, there is no key-press prompt. The USB boot process usually starts immediately.

Your computer should now boot from the flash drive or USB based external hard drive.

What happens now depends on what the bootable USB device was intended for. If you’re booting from Windows 10, Windows 8, or Windows 7 installation files on a flash drive, the operating system setup will begin. If you’re booting from a DBAN flash drive you created, it will start. You get the idea.

What to Do When the USB Device Won’t Boot

If you tried the above steps, but your computer didn’t boot from the USB device, check out some of the tips below. There are several places that this process can get hung up at.

Recheck the boot order in BIOS (Step 1). The number one reason a bootable flash drive or another USB device won’t boot is that BIOS isn’t configured to check the USB port first.

Didn’t find a «USB Device» boot order listing in BIOS? If your computer was manufactured around 2001 or before, it might not have this ability.

If your computer is newer, check for some other ways that the USB option might be worded. In some BIOS versions, it’s called «Removable Devices» or «External Devices.»

Remove other USB devices. Other connected USB devices, like printers, external media card readers, etc., could be consuming too much power or causing some other problem, preventing the computer from booting from a flash drive or another device. Unplug all other USB devices and try again.

Or, if you have multiple bootable devices plugged in at once, the computer might simply be booting to the wrong device, in which case the easiest fix would be to remove all USB storage devices but the one you want to use right now.

Copy the files to the USB device again. If you created the bootable flash drive or external hard drive yourself, which you probably did, repeat whatever steps you took again. You may have made a mistake during the process.

See How to Burn an ISO File to USB if you started with an ISO image. Getting an ISO file onto a USB drive, like a flash drive, isn’t as easy as just expanding or copying the file there.

Switch to another USB port. The BIOS on some motherboards only checks the first few USB ports. Switch to another USB port and restart your computer.

Update your motherboard’s BIOS. If your computer is ancient, the BIOS version running on the motherboard may not support booting directly from a USB device. Try flashing the BIOS and checking again for this feature.

How to Install Windows 7 From USB

A tutorial on using a USB flash drive to install Windows 7

Chances are you’ll need to install Windows 7 from a USB device if you have a tablet, a small laptop, or a netbook device, few of which include optical drives as standard hardware.

As of January 2020, Microsoft no longer supports Windows 7. We recommend upgrading to Windows 10 to continue receiving security updates and technical support.

Prepare for the Installation

You must migrate the Windows 7 setup files onto a flash drive (or any USB-based storage) and then boot from that flash drive to get the Windows 7 installation process started. However, simply copying the files from your Windows 7 DVD to a flash drive won’t work. You have to specially prepare the USB device and then properly copy the Windows 7 install files to it before it’ll work as you expect.

You’re in a similar, but slightly easier to solve, situation if you’ve purchased a Windows 7 ISO file directly from Microsoft and need that on a flash drive.

No matter what situation you’re in, just follow the instructions below to install Windows 7 from a USB device.

The following tutorial applies equally to whatever edition of Windows 7 you have a disc or ISO image of: Windows 7 Ultimate, Professional, Home Premium, etc.

What You’ll Need

• A Windows 7 ISO or DVD
• Access to a computer with Windows 7, 8, 10, Vista, or XP installed and working properly, as well as with a DVD drive if you have a Windows 7 DVD
• A 4 GB (or larger) flash drive

How to Install Windows 7 From USB

Correctly preparing a USB drive for use as an installation source for Windows 7 will take around 15 to 30 minutes depending on your computer speed and what edition of Windows 7 you have on DVD or in ISO format

Start with Step 1 below if you have a Windows 7 DVD or Step 2 if you have a Windows 7 ISO image.

Create an ISO file from the Windows 7 DVD. If you already know how to create ISO images, fantastic: do it, and then come back here for further instructions on what to do with it.

If you’ve never created an ISO file from a disc before, check out the tutorial linked above. It’ll walk you through installing some free software and then show how to use it to make the ISO. An ISO image is a single file that perfectly represents a disc—in this case, your Windows 7 installation DVD.

Next, we’re going to work on properly getting that Windows 7 ISO you just created onto the flash drive.

Download Microsoft’s Windows 7 USB/DVD Download Tool. Once downloaded, execute the file and follow the installation wizard.

This free program from Microsoft, which works in Windows 10 through Windows XP, will correctly format the USB drive and then copy the contents of your Windows 7 ISO file to the drive.

Pick the en-US.exe download for the English edition of this tool.

Start the Windows 7 USB DVD Download Tool program, which is probably located in your Start menu or on your Start screen, as well as on your Desktop.

On the Step 1 of 4: Choose ISO file screen, click Browse.

Locate and select your Windows 7 ISO file, and then click Open.

If you downloaded Windows 7 directly from Microsoft, check for the ISO image wherever you tend to store downloaded files. If you manually created an ISO file from your Windows 7 DVD in Step 1 above then it will be wherever you saved it to.

Click Next once you’re back on the Step 1 of 4 screen.

Click USB device on the Step 2 of 4: Choose media type screen.

On the Step 3 of 4: Insert USB device screen, choose the flash drive or external hard drive you want to put the Windows 7 installation files on.

If you haven’t yet plugged in the flash drive or other device you’re using, you can do that now. Just click the refresh button to make it show up in the list.

Click the Begin copying button.

Click Erase USB Device if you’re prompted to do so on a Not Enough Free Space window. Then click Yes to the confirmation in the next window.

If you don’t see this it just means that the flash drive or external hard disk you’ve selected is already empty.

Any data you have on this USB drive will be erased as part of this process.

On Step 4 of 4: Creating bootable USB device, wait for the program to format the USB drive and then copy the Windows 7 installation files to it from the ISO image you provided.

You’ll see a Status of Formatting for several seconds, followed by Copying files. This part might take as long as 30 minutes, maybe even longer, depending on which edition of Windows 7 the ISO file you have is from, as well as on how fast your computer, USB drive, and USB connection is.

The percentage complete indicator may sit on one or more percentages for a long time. This apparent pause doesn’t mean anything is wrong.

The next screen you see should say Bootable USB device created successfully, with a Status of Backup completed.

You can now close the Windows 7 USB DVD Download Tool program. The USB drive can now be used to install Windows 7.

Boot from the USB device to start the Windows 7 setup process.

You might need to make changes to the boot order in BIOS if the Windows 7 setup process doesn’t start when you try to boot from the USB drive. See How to Change the Boot Order in BIOS if you’ve never done that.

If you still can’t get the flash drive to boot, and you also have a UEFI based computer, see the information at the bottom of this page.

If you arrived here from How to Clean Install Windows 7, you can now return to that tutorial and continue installing Windows 7.

You should have now installed Windows 7 by USB.

Tips & More Information

When the Windows 7 USB DVD Download Tool formats the flash drive during the process above, it does so using NTFS, a file system that some UEFI systems won’t boot from if present on a USB stick.

To get the USB drive to boot on these computers, you should copy the data from the flash drive onto a folder on your computer, then reformat the flash drive using the older FAT32 file system, and then copy that same data back onto the drive.

See How to Burn an ISO File to USB for an alternative method for getting a Windows 7 ISO image onto a USB drive.