How to make a bootable USB drive

Need to boot your PC from a USB thumb drive? We show you how to make a USB flash drive bootable, for installing operating systems and motherboard BIOS updates.

In this guide, we’ll show you how to make a bootable USB drive. This will enable you to boot your PC directly from a USB flash drive, rather than the SSD or hard drive on which your operating system is installed. This can be handy if you want to flash your motherboard BIOS, as well as if you want to create a bootable drive for installing an operating system. We’re going to use the command prompt in Windows, so you don’t need to download any extra third-party software.

At Custom PC, we’ve been building PCs since 2003, giving us loads of experience in the process of assembling a rig and setting up PC hardware. We know exactly what tools you need and which methods work best.

1. Insert USB flash drive into USB port

How to make a bootable USB drive: USB 3 flash drive in USB port

You’ll need a USB flash drive that has a large enough capacity to hold the software you want to boot. This will be detailed in the documentation for the software, but USB flash drives with plenty of storage are readily available now. We recommend using at least a USB 3 model, so you won’t be waiting around for files to copy across to it. We’re using a 32GB SanDisk Ultra Fit drive. Insert your USB flash drive into a free USB 3 port on your PC.

2. Run the command prompt

How to make a bootable USB drive: Search Windows Start menu for command prompt

The next step is to open the command prompt in Windows. There are a number of ways to do this, but we find the quickest way to find it is to simply click on the Windows button and enter cmd into the Search bar. This will bring up the command prompt in the search results, and you just need to click on it to open it.

3. Run DiskPart

How to make a bootable USB drive: Run DiskPart at command prompt

We’re now going to run Windows’ command prompt disk partitioning utility. You simply need to type diskpart next to the command prompt, and this will spawn another command prompt window that will enable you to create a bootable partition on your USB flash drive.

4. Find your USB flash drive

How to make a bootable USB drive: Type list disk to list the physical drives in your PC

You absolutely don’t want to accidentally wipe your main SSD here, so it’s important to find which disk the command prompt sees as your USB flash drive. Type list disk next to the DISKPART prompt in the DiskPart command prompt Windows. This will bring up a list of all the physical drives in your PC. In our case, our 32GB USB flash drive is Disk 2, which has 28GB of usable space.

5. Select your USB flash drive

How to make a bootable USB drive: Select USB flash drive in DiskPart

To select your USB flash drive, type select disk x, where x is the number of your disk in the list above. In our case we typed select disk 2 in order to select our 32GB USB flash drive.

6. Wipe USB flash drive clean

How to make a bootable USB drive: Clean disk in DiskPart

We now need to clear all the data off your USB flash drive. If there’s anything you want on here, then type exit to get out of DiskPart, and then use Windows to back up any files you still want on your flash drive. You can then restart the process and go through all the above steps again. When you’re okay to wipe your USB flash drive, type clean at the DiskPart prompt.

7. Create partition on USB flash drive

How to make a bootable USB drive: Create and select partition in DiskPart

We now need to create the partition from which your PC will boot. Type create partition primary at the DISKPART prompt, which will create the partition. We now need to select this partition to ensure that the commands in the next step will apply to it. Type select partition 1 at the DISKPART prompt.

8. Format partition on USB flash drive

How to make a bootable USB drive: Format partition in DiskPart

We’re now going to quickly make this partition readable by formatting it. We’re going to type format fs=ntfs quick at the DISKPART prompt, which will format the drive with NTFS, which is the file system used by Windows. However, you can replace ntfs in the command above with fat32 if your chosen software requires the older FAT32 file system – format fs=fat32 quick  – FAT32 is commonly the required standard for flashing your BIOS, for example. See our full guide on how to flash your BIOS if this is what you want to do.

9. Make partition bootable

How to make a bootable USB drive: Make partition bootable in DiskPart with active command

Finally, we need to make our partition bootable, which is easy. Just type active at the DISKPART prompt. You now have bootable USB flash drive. Type exit to get out of DiskPart, and again to close down the command prompt. You now just need to copy the files you need for your software, such as for flashing your motherboard BIOS, in Windows.

That’s a wrap for our guide on how to make a bootable USB flash drive. Your next step, if you want your PC to boot from it, is to enter your motherboard BIOS or EFI, and make your USB flash drive the primary boot device.

If you’re looking to build a new PC, make sure you read our full guide on how to build a gaming PC, and check out our full guide on the best SSD for gaming, where you can find loads of recommendations for solid state drives at a range of speeds and prices to suit your needs.