How to format bootable usb before iso windows 8.1​？

Formatting a USB drive is a crucial step before installing Windows 8.1. especially if the USB drive is being repurposed from a previous installation or data transfer task. When creating a bootable USB drive for installing an operating system, the formatting ensures that the drive is properly set up to support the Windows 8.1 installation files. 

1. Importance of Formatting a USB Drive

Before delving into the specifics of how to format a bootable USB drive, it’s essential to understand why this process is necessary. A bootable USB drive is a storage medium from which a computer can boot an operating system. In the case of Windows 8.1. this means preparing the USB drive with the appropriate file system and partition structure to ensure it can load the installation files when the computer starts.

Why Formatting is Necessary

Clear Old Data: If the USB drive has been used before, especially as a bootable drive for other OS installations, there might be leftover data or partition information that could cause issues. Formatting ensures that all old data is cleared.

Correct File System: Windows installation requires a specific file system to function properly. Formatting ensures that the drive is set up with the correct system (e.g., FAT32 or NTFS).

Create a Bootable Partition: A USB drive must have a proper boot partition to be recognized by the BIOS/UEFI of the target machine. Formatting prepares the drive to support this setup.

How Formatting Affects Bootable USB Drives When you format a USB drive for use with Windows installation, you also need to ensure it has a bootable partition. The partition must be set up in such a way that the BIOS of your computer can identify and use it to start the OS installation process. During the formatting process, the drive will be wiped clean, which makes it necessary to back up any important data beforehand.

2. Preparing for the Format

Before beginning the formatting process, you should take a few preparatory steps to ensure the task goes smoothly.

Backing Up Data Formatting a USB drive erases all data stored on it. Therefore, it is vital to back up any important files before you proceed. Copy your files to another storage device or cloud service for safekeeping. Once the drive is formatted, recovering lost files can be challenging.

Checking the USB Drive Capacity Ensure your USB drive has sufficient capacity to hold the Windows 8.1 ISO files. The ISO file for Windows 8.1 is typically around 4 to 5 GB, so a USB drive with at least 8 GB of available space is recommended. If your USB drive is smaller than this, you may need to consider purchasing a larger one.

3. How to Format a USB Drive Using Windows (via Disk Management)

Disk Management is a built-in tool in Windows that allows you to manage disks and partitions. Here’s a step-by-step guide for formatting your USB drive:

Step 1: Open Disk Management

Press the Windows key and type “Disk Management.”

Click on Create and format hard disk partitions from the search results.

Step 2: Select the USB Drive

In the Disk Management window, look for the USB drive listed under the “Volume” section. Be sure to identify it correctly by checking the size and other details.

Step 3: Right-Click and Format

Right-click on the USB drive and select Format.

In the Format dialog, ensure that the following options are selected:

File System: Choose FAT32 for drives up to 32 GB or NTFS for larger drives.

Allocation Unit Size: Leave this as default.

Volume Label: You can name your drive here, such as “Windows 8.1 USB.”

Perform a Quick Format: This option is recommended for faster formatting.

Step 4: Confirm the Format

Click OK to begin the formatting process. Disk Management will take a few moments to format the drive, and once it’s done, your USB drive will be ready for use.

4. How to Format a USB Drive Using Command Prompt (Diskpart)

If you prefer using the Command Prompt, the Diskpart utility is a powerful tool for managing disks and partitions. Here’s how to format your USB drive using Diskpart:

Step 1: Open Command Prompt as Administrator

Press the Windows key, type “Command Prompt,” right-click on it, and select Run as administrator.

Step 2: Launch Diskpart

In the Command Prompt window, type the following command and press Enter:

diskpart

Step 3: List the Disks

To view a list of all connected disks, type:

list disk

Identify the number of your USB drive by its size.

Step 4: Select the USB Drive

Type the following command, replacing “X” with your USB drive’s number:

bash

select disk X

Step 5: Clean the Drive

To wipe the drive, type:

clean

Step 6: Create a Primary Partition

Type the following command to create a new primary partition:

sql

create partition primary

Step 7: Format the Partition

To format the partition, type:

lua

format fs=fat32 quick

(For larger drives, use NTFS instead of FAT32.)

Step 8: Assign a Drive Letter

To assign a drive letter to the partition, type:

objectivec

assign letter=X

Replace “X” with the letter you want for the USB drive.

Step 9: Exit Diskpart

Finally, type:

bash

exit

Your USB drive is now formatted and ready for use.

5. How to Format a USB Drive Using Third-Party Tools

There are several third-party tools available that make formatting USB drives a breeze. Two popular options are Rufus and HP USB Disk Storage Format Tool.

Using Rufus: Rufus is a free, open-source tool designed specifically for creating bootable USB drives. To format your USB drive with Rufus, follow these steps:

Download and install Rufus from its official website.

Launch the program and select your USB drive from the device list.

Choose the partition scheme (GPT for UEFI, MBR for BIOS) based on your system’s requirements.

Under “File System,” select FAT32 or NTFS.

Click Start to format the USB drive.

Using HP USB Disk Storage Format Tool: This is another popular tool for formatting USB drives, particularly useful for older drives:

Download and install the tool.

Open the tool and select your USB drive.

Choose FAT32 as the file system (for drives under 32 GB).

Click Start to format.

6. Creating a Bootable USB Drive for Windows 8.1 Installation

Once your USB drive is formatted, the next step is to create a bootable USB drive with the Windows 8.1 installation files.

Step 1: Download the Windows 8.1 ISO

Go to the official Microsoft website and download the Windows 8.1 ISO file. Ensure you download the correct version (32-bit or 64-bit).

Step 2: Use Rufus to Create a Bootable USB Drive

Open Rufus and select your formatted USB drive.

Under “Boot selection,” select Disk or ISO image and browse to the Windows 8.1 ISO file you downloaded.

Set the Partition Scheme to GPT for UEFI or MBR for BIOS, depending on your system.

Click Start to begin creating the bootable USB drive.