You’ve connected a USB flash drive, heard the familiar Windows sound of connection, yet no drive letter shows up. You then go into Disk Management for Windows and see the device and memory, but the USB flash drive doesn’t get assigned a drive letter.

What should you do?

Most of the time, Windows will automatically assign a drive letter to any connected storage device—whether it’s a USB stick, USB hard drive, or other mass storage device.

However, if a drive letter isn’t assigned, there’s a quick fix to get your computer working properly again:

1. Open Command Prompt as Administrator (search for CMD, then right-click and select “Run as Administrator”).
2. Type diskpart and press Enter.
3. Once in DISKPART, type automount enable and press Enter.

If the above steps don’t solve the problem, there could be conflicting registry entries from past USB devices that disabled or interfered with the automount function.

Nexcopy offers a registry cleaning tool specifically designed for USB devices connected to your computer. This utility is an executable file that requires no installation and contains no spyware or malware. Nexcopy is a reputable company that provides direct support via phone, email, or live chat, so you can trust their software is safe and reliable.

USBScrub is the utility name and is available for download here.

We’ve seen these terms floating around forums and how-to articles for years when someone is explaining what to do with USB flash drives. Most people gloss over the definitions of Clean, Erase, and Format because the terms sound interchangeable or because they are not planning to perform the task being discussed.

The goal of this article is to clearly explain the differences between Clean, Erase, and Format so you can better understand what people mean when discussing USB flash drive maintenance and data removal.

All of the functions below can be performed on a Windows 10 system or newer. We’ll start with the simplest operation and work toward the more advanced ones.

Format

Formatting is what roughly 98% of Windows users rely on. This is the graphical option you see when you right-click a drive letter in Windows Explorer and select “Format.” But what does this function actually do?

Formatting is the least complicated option. It removes the file allocation table from the USB flash drive and creates a new one. Put simply, the operating system deletes the index that tells Windows where files are stored, making the drive appear empty.

The important detail is that the data itself still exists on the drive. It is no longer organized in a way that Windows can easily display, but the underlying information remains intact.

Using basic file-recovery tools, like the one we reviewed previously, it is often possible to recover most or all of the files that were on the drive.

The image below illustrates this concept. The light-gray area represents data that still exists on the flash memory but is no longer referenced by the file system. Recovery software scans this space to reconstruct files. Notice that the boot code area of the drive is untouched during a standard format.

If you’re wondering whether a flash drive should be formatted as FAT, FAT32, exFAT, or NTFS, we previously published a detailed comparison covering those file systems.

Clean

The Clean function goes a step further than formatting. It directly targets the Master Boot Record and partition information of the USB flash drive.

Running Clean removes the boot code and deletes all partitions. The partition data is what tells a computer how large the drive is and whether it can be used as a bootable device.

The Clean function is not available through the standard Windows graphical interface. It can only be accessed through the Windows command-line utility DiskPart.

The image below highlights the boot code area affected by the Clean command. While this portion of the drive is cleared, the actual data area remains intact, which is why Clean executes very quickly.

The most common reason to use Clean is troubleshooting. If a flash drive contains data but no longer behaves correctly when connected to a computer, clearing corrupted boot or partition information can sometimes restore functionality while preserving recoverable data.

To run Clean on a USB flash drive:

• Type diskpart into the Windows search bar and press Enter
• Type list disk and press Enter
• Identify which disk number corresponds to your USB flash drive
• Type select disk 1 (replace 1 with your USB’s disk number) and press Enter
• Type clean and press Enter
• DiskPart will confirm when the process is complete

After running Clean, the drive will appear as RAW and unreadable to Windows. To make it usable again, open Disk Management, locate the unallocated space, create a new simple volume, and follow the formatting wizard.

Clean All

The Clean All command is the most thorough option. Like Clean, it is only available through DiskPart, but it also writes zeros across the entire memory space of the flash drive.

This means all previous data is physically overwritten. Once Clean All is complete, file recovery is no longer possible.

For readers familiar with Department of Defense data-destruction methods, Clean All is conceptually similar to a single-pass overwrite. Traditional DoD methods repeat this process multiple times using different patterns.

Common reasons to use Clean All include securely handing a drive to another person, recycling a USB flash drive, or ensuring a virus is completely removed.

To run Clean All, follow the same DiskPart steps as Clean, but replace the final command with clean all. Because the entire memory space is overwritten, this process can take significant time depending on drive capacity.

This tutorial applies to Windows 7, Windows 8, and Windows 10 systems. Administrator privileges are required to use DiskPart’s Clean and Clean All commands.

This article was inspired by a forum discussion on TenForums.com.

The link below is for a ZIP file that contains two batch files to either enable or how to disable USB write protection on a Windows 10 computer. These batch files also work on Windows 7 machines.

This solution is ultra-easy and very quick: one click to run the registry edit file and one click to confirm the task. That’s it.

Typically, a person will want to lock down the USB ports of a computer to ensure a virus doesn’t spread through a USB device, such as a flash drive. This batch file provides a fast and simple way to both lock down your USB ports and easily unlock them again.

Important: Do not have a USB flash drive connected to the system when you run either batch file.

For those seeking more technical details, here is the specific registry edit being applied. Changing the DWORD value to 00000001 sets the device policy for the computer to be write-protected. Changing that value back to 00000000 restores normal read/write access.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\
StorageDevicePolicies]
“WriteProtect”=dword:00000001

Note: This USB write protection method is specific to the PC on which it is applied. It is not device-specific and will not follow the USB drive to other machines.

If you require USB write protection that is permanent on the device itself and universal across all computers, contact Nexcopy.com and ask about their Lock License USB drives. This hardware-level solution is embedded in the USB controller, ensuring the drive is always write-protected, preventing any possibility of a virus being written to the USB stick. This is the best universal solution for USB write protection.

Screenshots of the Batch File Process

Batch files included in the ZIP:

Windows confirmation prompt after running the batch file:

Task completion screen:

Download link for the two batch files:

USB Write Protection Registry Edit Batch Files

USB 3.2, the most recent widely deployed standard at the time of its introduction, supports maximum transfer speeds of up to 20Gbps under its fastest configuration. USB4 builds on that foundation and raises the ceiling to 40Gbps, with the newer USB4 Version 2 specification extending bandwidth even further to a theoretical 80Gbps. Put another way, 80Gbps is equivalent to moving roughly 10,000MB of data in a single second, or about 10GB per second.

Keep in mind this is all theoretical maximum throughput. Real-world performance will always be lower due to protocol overhead, controller limitations, cable quality, and storage speed. That gap between headline numbers and actual transfer rates has always existed and will continue to do so.

USB4 is built on Intel’s Thunderbolt technology, a high-speed interface Apple strongly promoted starting around 2012. While Thunderbolt delivered excellent performance, licensing costs and strict certification requirements kept accessory prices high and limited widespread adoption. Intel’s long-term goal was always to merge Thunderbolt into USB, bringing higher speeds to the mainstream at more affordable price points.

USB4 maintains backward compatibility with USB 3.2, USB 2.0, and Thunderbolt 3 devices. Because the standard fully embraces the USB-C connector and unifies multiple protocols, manufacturers can design fewer ports while supporting more use cases. As USB4 adoption increases, faster cables, docks, and storage devices are already becoming more common and less expensive.

USB4 devices are also required to support USB Power Delivery, which intelligently manages charging and power negotiation. This allows everything from smartphones to high-performance laptops to draw the correct wattage safely and efficiently from the same port.

Early USB4 products began appearing in the market in 2020, and today the ecosystem is steadily expanding as controllers, cables, and host systems mature. This post was originally prompted by the release of the finalized specification from the governing body, USB-IF, and the momentum behind USB4 has only increased since then.