USB Flash Drive Doesn't Format
A computer may refuse to format a USB flash drive because the device's storage volume is secured or the device is physically damaged. The computer will either refuse to format or error-out of the format process if something is not properly configured with the flash drive. Flash drives with configuration or permission-based problems can be worked around within Windows.
1 Use the Disk Management Tool
Connected flash drives can be formatted within the Windows Disk Management tool. If the flash drive is using an unrecognized file system or is not formatted at all it will not appear in File Explorer, making the right-click menu "Format" option unavailable to the user. You can run the tool by pressing "Windows-R," entering "diskmgmt.msc" and clicking "OK." The connected flash drive will appear in the device list on the bottom section of the Disk Management window. You can delete an existing unsupported volume by right-clicking on it and selecting "Delete Volume." You can create a new, compatible volume by right-clicking on the unallocated space and selecting "New Simple Volume." Follow the onscreen instructions to complete the process.
2 Troubleshoot Credentials and Device Use
Windows may reject the format command if the user doesn't have administrative privileges or the flash drive is in use. To troubleshoot, shut down the computer, disconnect the flash drive, reboot the computer, log in as a user with administrative privileges and reconnect the flash drive.
3 Unlock the Drive Partition
Windows will not format a write-protected USB flash drive; as far as the computer is concerned, formatting the device is a form of writing. You can remove write-protection from a flash drive with Diskpart. To launch a command prompt, press "Windows-R," type "cmd" and press "Enter." To clear the write protection, type "diskpart," press "Enter," type "list disk" and press "Enter" again to bring up the device list. Determine which device is the flash drive based on the capacity listed under "Size." Type "select disk X" (where "X" is the listed number of the flash drive) and press "Enter." Type in the command "attributes disk clear readonly," press "Enter" and exit the command prompt when the process completes.
4 Sector Damage Holdups
Storage devices are broken up into sectors to help with data organization and location. A bad sector is one that's damaged and can't be read -- damaged sectors can disrupt the format process. You can check for and repair sector damage by right-clicking on the flash drive in File Explorer, selecting "properties," opening the "Tools" tab and clicking the "Check now" option under "Error-checking."
5 Damaged Hardware Problems
Hardware damage can make all of or part of the flash drive inaccessible to the computer; the computer can't format the device if it can't use it. Professional repair technicians can swap out broken connectors and circuit boards on damaged flash drives. However, the process may cost more than the replacement cost of the flash drive itself. The device is a lost cause if the flash memory itself has failed.