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10 Tech How-To

How to Create UEFI Bootable USB on Windows 10

Guide 10-42583 · Updated · Step by step

This guide walks you through creating a UEFI bootable USB drive on Windows 10, so you can install or repair Windows, run a live Linux environment, or use diagnostic tools. You’ll need a USB drive (at least 8 GB for most ISOs), the ISO file of the OS or tool you want to boot, and a Windows 10 PC. The process uses either built-in tools or free third-party utilities, and we’ll cover both.

What You’ll Need

  • A USB flash drive (8 GB or larger; 16 GB is safer for larger ISOs).
  • The ISO file of the operating system or utility you want to boot (e.g., Windows 10, Ubuntu, GParted).
  • A Windows 10 PC with admin rights.
  • Optional: a free tool like Rufus or Ventoy (we’ll show Rufus as it’s widely used).

Step-by-Step

  1. Back up your USB drive. Formatting erases everything. Copy any files you need to your PC.
  2. Download the ISO file. Get the official ISO from the software vendor (e.g., Microsoft’s Media Creation Tool for Windows, Ubuntu’s download page). Save it somewhere easy to find, like your Desktop.
  3. Plug in the USB drive. Insert it into a USB port on your PC. Note the drive letter (e.g., E:) in File Explorer.
  4. Choose your method. You can use Windows’ built-in tools (Diskpart + DISM) or a third-party tool. For most users, Rufus is simpler and more reliable. We’ll cover both.
  5. Method A: Using Rufus (recommended)
    1. Download Rufus from the official site (rufus.ie). It’s a single executable, no install needed.
    2. Run Rufus. In the “Device” dropdown, select your USB drive.
    3. Click “SELECT” next to “Boot selection” and choose your ISO file.
    4. For “Partition scheme”, choose GPT (for UEFI). For “Target system”, choose UEFI (non CSM).
    5. File system: leave as NTFS (for Windows) or FAT32 (for Linux/older tools). Rufus usually picks the right one automatically.
    6. Click “START”. If prompted about writing in ISO or DD mode, choose ISO mode (recommended) and click OK.
    7. Wait for completion. The status bar will show progress; when it says “READY”, you’re done.
  6. Method B: Using Diskpart and DISM (built-in, no extra tools)
    1. Open Command Prompt as Administrator (right-click Start > Command Prompt (Admin) or Windows PowerShell (Admin)).
    2. Type diskpart and press Enter.
    3. Type list disk to see all disks. Identify your USB drive by its size (e.g., Disk 2). Be careful not to pick your system drive.
    4. Type select disk 2 (replace 2 with your USB’s number).
    5. Type clean to wipe the drive.
    6. Type convert gpt to make it GPT (required for UEFI).
    7. Type create partition primary, then format fs=fat32 quick (or NTFS if the ISO is larger than 4 GB and you’re using Windows setup).
    8. Type assign to give it a drive letter, then exit.
    9. Mount the ISO by double-clicking it in File Explorer. Note the virtual drive letter (e.g., F:).
    10. In the same admin Command Prompt, type xcopy F:\*.* /s /e /f /i E:\ (replace F: with your ISO’s drive letter and E: with your USB’s). This copies all files.
    11. For Windows 10/11 ISOs, you may need to copy the install.wim file separately if it’s larger than 4 GB (FAT32 limit). Use dism /Split-Image /ImageFile:F:\sources\install.wim /SWMFile:E:\sources\install.swm /FileSize:4000 to split it.
  7. Verify the USB boots. Restart your PC, enter the boot menu (usually F12, F2, Esc, or Del during startup), select your USB drive under “UEFI” (not “Legacy” or “USB-HDD”), and confirm it loads.

Common Mistakes

  • Choosing MBR instead of GPT. For UEFI, the partition scheme must be GPT. MBR works only in legacy BIOS mode.
  • Using FAT32 for Windows ISOs larger than 4 GB. The install.wim file exceeds the 4 GB limit. Use NTFS or split the file.
  • Booting in the wrong mode. Even if the USB is UEFI-ready, your PC may boot it in legacy mode if the boot menu shows both options. Always select the “UEFI” entry.
  • Not disabling Secure Boot. Some Linux ISOs and tools aren’t signed, so Secure Boot blocks them. Temporarily disable it in BIOS/UEFI settings.
  • Formatting the wrong drive. Double-check the disk number in Diskpart; wiping your system drive is catastrophic.

Tips

  • Use a USB 3.0 drive for faster boot and installation.
  • Keep a backup of your ISO file on your PC; you can recreate the USB anytime.
  • For multi-boot needs, use Ventoy—it lets you copy multiple ISOs to one drive without reformatting.
  • If your PC has both UEFI and legacy modes, set it to “UEFI only” in BIOS to avoid confusion.
  • After creating the USB, test it on a non-critical PC first if possible.

Troubleshooting

USB not recognized in boot menu: Try a different USB port (preferably a rear port on desktops). Ensure the drive is formatted in a supported file system. Recreate the drive with Rufus and select “GPT” again.

Boot fails with “No bootable device”: The USB may not be UEFI-bootable. Recreate it ensuring GPT and UEFI options. If using a Linux ISO, try DD mode in Rufus (when prompted).

Secure Boot error: Disable Secure Boot in BIOS/UEFI settings (usually under “Boot” or “Security” tab). For Windows installation, you can re-enable it after.

USB boots but shows a black screen: This often happens with incompatible graphics drivers or a corrupt ISO. Verify the ISO’s checksum, and try a different USB tool or a different USB drive.

Diskpart errors: If you get “Access Denied”, ensure you’re running Command Prompt as Administrator. If “The specified disk is not convertible” appears, the drive may be too small or already in use; clean it first with clean.

Frequently Asked Questions

Q: Can I use a USB drive smaller than 8 GB?
A: It depends on the ISO. Windows 10 is about 5-6 GB, so 8 GB is minimum. For smaller tools like GParted, 2 GB might suffice.

Q: Do I need to disable Secure Boot for Windows 10 installation?
A: No, Windows 10 is signed and works with Secure Boot. But some Linux distros and third-party tools may fail; disable it temporarily if needed.

Q: What’s the difference between UEFI and Legacy boot?
A: UEFI is the modern firmware interface, faster and supports GPT disks and Secure Boot. Legacy (BIOS) is older, uses MBR, and is slower. Most PCs after 2012 support UEFI.

Q: Can I use the same USB for both UEFI and Legacy?
A: Yes, with Rufus you can choose “MBR” and “UEFI (non CSM)” or “BIOS or UEFI” to make a hybrid. But for pure UEFI, GPT is best.

Q: Why does my USB show two entries in the boot menu?
A: One is for UEFI mode, the other for legacy. Always pick the one labeled “UEFI” (e.g., “UEFI: USB Drive”).

Q: How do I know if my PC uses UEFI?
A: In Windows, press Win+R, type msinfo32, and check “BIOS Mode”. If it says “UEFI”, you’re good. If “Legacy”, you may need to switch in BIOS.

Related

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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