How to Make a USB Bootable.

How to Make a  USB Bootable

Method 1:

Using Command Prompt on Windows

1. 
   1
   Insert a USB flash drive into your computer. Your USB flash drive should plug into one of the rectangular USB ports on your computer's housing. Flash drives only fit one way, so don't force the drive if it doesn't fit.
   

   • The USB flash drive should be at least 8 gigabytes in space so that it can accommodate most operating system installation files.
2. 
   2
   Open Start 
   

   

   . Click the Windows logo in the bottom-left corner of the screen.
3. 
   3
   Type in command prompt. This will search your computer for the Command Prompt program.
4. 
   4
   Right-click Command Prompt 
   

   

   . It's a black box at the top of the Start window. This will prompt a drop-down menu.
   

   • If your mouse doesn't have a right-click button, click the right side of the mouse, or use two fingers to click the mouse.
   • If your computer uses a trackpad instead of a mouse, use two fingers to tap the trackpad or press the bottom-right side of the trackpad.
5. 
   5
   Click Run as administrator. It's in the drop-down menu.
6. 
   6
   Click Yes when prompted. This will confirm your decision and open Command Prompt.
7. 
   7
   Enter the "partition" command. Type in diskpart and then press ↵ Enter to do so.
   

   • You may be prompted to confirm this decision before proceeding.
8. 
   8
   Bring up a list of connected drives. Type list disk into Command Prompt, then press ↵ Enter.
9. 
   9
   Find your USB flash drive. Look for your flash drive's name, letter, or size in gigabytes to identify it.
   

   • If you don't know which one is your flash drive, unplug your flash drive, run the "disk list" command, plug back in your flash drive, run the "disk list" command yet again, and figure out which disk was absent the first time that you ran the "disk list" command.
   • The flash drive is usually the bottom disk in this menu.
10. 
    10
    Select your flash drive. Type select disk number into Command Prompt—making sure to replace "number" with the flash drive's number as presented in the list—and then press ↵ Enter.
11. 
    11
    Erase the flash drive's contents. Type in clean and then press ↵ Enter.
12. 
    12
    Create a new partition on the flash drive. To do so:
    

    • Type in create partition primary and press ↵ Enter
    • Type in select partition 1 and press ↵ Enter
    • Type in active and press ↵ Enter
13. 
    13
    Format the flash drive. Type format fs=fat32 quick into Command Prompt, then press ↵ Enter.
    

    • If you encounter an error in the USB creation, repeat this process using the format fs=ntfs quick command instead.
14. 
    14
    Assign a letter to the USB drive. Type in assign and press ↵ Enter. You should see a confirmation message appear in the Command Prompt window.
15. 
    15
    Close the Command Prompt window(s). Your USB drive is now bootable, meaning that you can place an operating system's ISO file or an image of your computer's hard drive on the USB drive in order to install it on another computer.

16. Method 2:

    Using Terminal on Mac

    1. 
       1
       Insert a USB flash drive into your computer. Your USB flash drive should plug into one of the rectangular or oval USB or USB-C ports on your computer's housing. Traditional flash drives only fit one way, so don't force the drive if it doesn't fit.

       • If your Mac uses USB-C ports, your USB-C flash drive should fit any way in which you insert it.
       • The USB flash drive should be at least 8 gigabytes in space so that it can accommodate most operating system installation files.
    2. 
       2
       Make sure that you have an ISO file. If you want to create a bootable USB drive on a Mac, you'll need to have an ISO file (or an image file, if you're backing up your computer's hard drive) ready to drag and drop into Terminal.

       • This is different than how Windows handles bootable flash drives, since you can make a flash drive bootable and then save it for later when using Windows.
    3. 
       3
       Open Spotlight 

       

       . Click the magnifying glass icon in the top-right corner of the screen. A search bar will appear.
    4. 
       4
       Type in terminal. This will search your Mac for the Terminal application.
    5. 
       5
       Double-click Terminal 

       

       . It's a black box in the middle of the Spotlight search results. Doing so will open Terminal.
    6. 
       6
       Open a list of connected drives. Type diskutil list into Terminal, then press ⏎ Return.
    7. 
       7
       Find your USB drive. Look for the USB drive that you plugged into your computer, then look at the USB drive's name under the "IDENTIFIER" heading. You'll usually find your USB drive under the "(external, physical)" heading near the bottom of the Terminal window.

       • Your USB flash drive's name under the "IDENTIFIER" heading will normally be something like "disk1" or "disk2".
    8. 
       8
       Select the USB drive. Type diskutil unmountDisk /dev/disknumber—making sure to replace "disknumber" with the disk's "IDENTIFIER" name and number (e.g., disk2)—into Terminal, then press ⏎ Return.
    9. 
       9
       Enter the formatting command. Type in sudo dd if= but don't press the ⏎ Return key just yet.
    10. 
        10
        Drag the ISO file into the Terminal window. Click and drag the ISO file (or disk image file) that you want to boot into using the USB drive into the Terminal window. This will copy the file's address into the Terminal command.

        • You can also type in the folder path to the ISO file.
    11. 
        11
        Press the Space key. This will put a space at the end of the file's address, making room for the next command.
    12. 
        12
        Enter the rest of the command. Type in of=/dev/disknumber bs=1m, again making sure to replace "disknumber" with the USB flash drive's number (e.g., disk2), and press ⏎ Return.
    13. 
        13
        Type in your password. This is the password that you use to log into your Mac. As you type, you'll notice that the letters don't appear in Terminal; this is normal.
    14. 
        14
        Press ⏎ Return. Doing so submits your password and prompts your Mac to begin creating a bootable USB flash drive with your selected ISO or image file.

        • This process can take several hours to complete, so just leave Terminal open and your Mac plugged in.