Why Windows Cannot format USB drive?

USB drives, also known as flash drives or thumb drives, are extremely convenient for transferring files between computers and devices. However, sometimes Windows may encounter errors when trying to format a USB drive. There are several potential reasons why Windows cannot format a USB drive.

Corrupted File System

One of the most common reasons for Windows being unable to format a USB drive is file system corruption. USB drives typically use the FAT32 or exFAT file systems. Over time, these file systems can become corrupted from improper ejection of the drive or other errors. This prevents Windows from being able to fully format the drive.

Symptoms of Corrupted File System

  • Errors or warnings when trying to format the USB drive
  • Inability to add or delete files on the USB drive
  • “RAW” listed as the file system
  • Strange filenames or folder structures on the USB drive

Solutions for Corrupted File System

If the file system is corrupted, Windows disk utilities like DiskPart or Disk Management may not be able to fully format the USB drive. However, third-party formatting tools can often fix the corrupted file system by completely reformatting the drive. Some options include:

  • Using diskpart command line utility in Windows
  • Trying a different file system like exFAT instead of FAT32
  • Using third-party formatting tools like HDD Low Level Format Tool
  • As a last resort, low-level “zeroing out” the drive to totally reset it

Bad Sectors on the USB Drive

Another common reason for formatting issues is that the USB drive has developed bad sectors. Bad sectors are small damages on the physical storage medium that prevent data from being read from or written to those areas.

Symptoms of Bad Sectors

  • Errors or failed operations when reading or writing files
  • Unreadable areas on the USB drive
  • Difficulty formatting or partitioning the USB drive
  • Strange noises from the USB drive
  • Slower performance than expected

Checking for Bad Sectors

To confirm if bad sectors are causing the formatting issues, you can scan for errors using the CHKDSK utility in Windows. Simply type “chkdsk X: /f” (replacing X with the correct drive letter) at the command prompt. CHKDSK will attempt to repair any bad sectors it finds.

Alternatively, tools like HDD Scan can do a more thorough scan for physical defects on the drive platters.

Solutions for Bad Sectors

  • Run error checking and let CHKDSK try to repair bad sectors
  • Use HDD manufacture’s tools to scan and repair defects
  • Back up data and perform a full format of the USB drive
  • As a last resort, replace the USB drive if defects cannot be repaired

Outdated USB Drivers in Windows

Problems formatting USB drives may also be caused by buggy, corrupt, or outdated USB drivers in Windows. The USB drivers are software that enables communication between USB devices and the Windows operating system.

Symptoms of USB Driver Issues

  • Frequent errors or crashes when inserting USB devices
  • USB devices not being recognized or detected
  • Errors or failures when accessing USB devices
  • Issues affecting multiple USB devices, not just one

Updating USB Drivers

To fix USB driver problems, you should first update your USB drivers to the latest available versions. This can be done by:

  • Using Windows Update to install the latest USB updates
  • Visiting your hardware manufacturer’s website for the newest drivers
  • Manually uninstalling and reinstalling the USB drivers
  • Using a driver update utility to download updated USB drivers

Updating your USB drivers will often resolve general USB problems and allow USB devices like flash drives to be formatted properly.

Disk Write Protection Enabled

Some USB drives come with disk write protection enabled by default. This is an optional security setting which prevents any changes being made to the drive, essentially locking it as read-only. With write protection enabled, Windows cannot format the USB drive.

Checking for Write Protection

To determine if disk write protection is causing the issue, check for a small switch on the housing of the USB drive. Sliding the switch one direction will enable write protection, while sliding it the other way disables protection and allows writing to the drive.

Alternatively, go to Device Manager, find the USB drive, and check under Policies to see if Write Protect is enabled.

Disabling Disk Write Protection

  • Slide the physical write protect switch on the USB drive housing
  • Use registry editor to change the WriteProtect value to 0 in Device Manager
  • Use diskpart to remove write protection with “attributes disk clear readonly”

Disabling write protection will allow Windows to format the USB drive normally.

Partition Issues on the USB Drive

If the USB drive has pre-existing partitions, this can sometimes interfere with Windows being able to format it. Partition issues may prevent Windows from formatting the full drive.

Symptoms of Partition Issues

  • Formatting failing with “unable to access drive” errors
  • Multiple drive letters assigned to one USB drive
  • Some space on USB drive shows as unallocated
  • USB drive contains strange or unknown partitions

Checking Partition Configurations

To view the partition layout of your USB drive, use the Windows Disk Management utility. This will show all partitions on the drive and identify any unknown, damaged, or unusual partitions.

Fixing Partition Issues

To resolve any partition issues, you may need to completely wipe and recreate the partition table on the USB drive. This can be done by:

  • Using diskpart “clean” command to delete all partitions
  • Using Disk Management to delete volumes and create a new simple volume
  • Using third-party partitioning tools to wipe and re-partition the drive

Removing old or unnecessary partitions will allow Windows to do a clean format of the USB drive.

Damaged USB Port or Hardware

In some cases, there may be physical damage to the computer’s USB ports or the USB device itself that prevents proper formatting. USB hardware damage can lead to communication errors with connected devices.

Signs of Physical USB Damage

  • Loose, damaged USB ports on computer
  • USB device has physical damage or broken parts
  • Problems only occur with one specific USB port
  • USB device gets hot or makes abnormal noises

Testing other USB Devices / Ports

To determine if USB hardware damage is the culprit, try plugging the USB drive into other USB ports and see if the issue persists. Also test different USB devices in the problematic port. This can reveal if the problems are isolated to a damaged port or device.

Repairing Damaged Components

  • Replace damaged USB cable, housing, connectors
  • Replace internal USB host controller if motherboard USB is damaged
  • Use external USB hub or card if needed to bypass damaged ports

Replacing any damaged USB hardware components will be needed to allow proper communication and formatting.

Insufficient Power Delivery

Some USB flash drives with very large storage capacity may also run into issues being formatted properly due to insufficient power delivery over the USB port. The USB port may not provide enough consistent power to fully run the USB drive.

Signs of Insufficient Power

  • Large high-capacity USB drives (64GB+) having issues
  • Problems only occur when connecting USB hub or multiple devices
  • Errors or failures during large file transfers
  • USB drive disconnecting or powering down during use

Solutions for Insufficient Power

  • Use rear motherboard USB ports instead of front case ports
  • Plug USB drive directly into computer instead of hub
  • Use USB Y-cable with additional power connection
  • Use external powered USB hub with adapter

Providing consistent and adequate power delivery to the USB drive can allow formatting to work properly.

Non-Windows Formatted Drive

On rare occasions, a USB flash drive may have been formatted with a non-Windows file system that is not supported by the OS. Examples include Linux EXT formats, NTFS versions not compatible with the computer’s Windows version, etc.

Identifying Unsupported File Systems

Inserting the USB drive into a Windows computer will show an “unrecognized” or “unsupported” file system message under Computer management. The format utility will also indicate the drive is currently formatted with an incompatible file system.

Reformatting the Drive

To allow reformatting in Windows, the current non-Windows file system needs to be erased. This can be done by:

  • Using diskpart “clean” command to delete existing partitions
  • Using third-party tools like HDD Low Level Format Tool
  • As a last resort, zeroing out the drive to completely reset it

With the non-Windows file system erased, Windows will be able to do a clean format of the USB drive.


Windows being unable to format a USB drive properly is often due to file system corruption, bad sectors, partition issues, or unsupported formats on the drive itself. Updating USB drivers, ensuring sufficient power, and checking for hardware damage can also help resolve formatting problems. Resetting, reformatting, or replacing the USB drive may be necessary if software fixes do not work. Following proper troubleshooting steps can identify the root cause and allow you to recover the use of your USB flash drive on Windows.