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

The most common reason why only one USB drive can be used in Windows is due to multiple USBs connected with the same USB device signature, or disk signature collision.

If you are dealing with bootable devices and seeing this problem, we are confident a collision is the issue. If you are not dealing with a bootable device, then our information below will probably not help.

What is a USB signature collision?

A signature collision can happen on any bootable device, such as Compact Flash cards, SD cards, microSD cards, and USB flash drives. A disk signature is a unique identifier number (UID). It is a unique identifier stored as part of the MBR (Master Boot Record) for an operating system loaded on the device. The operating system uses the UID to identify and distinguish between storage devices. It is commonly made up of eight alphanumeric characters. A disk collision occurs when your operating system (Windows) detects that there are two disks with identical signatures.

For Windows 7, 8, 8.1, and 10, these versions of Windows will disable the second drive and will not allow that second volume to mount until the disk collision has been rectified. If you are reading this article, chances are, this is exactly what is happening to you.

The first thing to do is navigate to the Disk Management tool within Windows. To do this, use the search tool and type in Disk Management. This will take you to the utility that Windows offers. Here you can see your multiple devices connected. If you click or hover over the device not working you will see one of two messages:

“The boot selection failed because a required device is inaccessible” or “This disk is offline because it has a signature collision.”

What created the USB disk signature collision?

Making a bit-by-bit copy of one device to another, like using a USB duplicator, would create a disk signature collision. Because these binary duplicators copy the MBR information, that UID is also copied to the target device. Stepping forward, once those two devices are connected to the same computer, “boom” you get the collision.

Chances are, the situation you are in right now is due to a cloning process you have just completed. But don’t worry, we have the fix!

Fixing a USB disk signature collision

There are two methods for fixing the collision issue. The first solution is using DiskPart, which is a free command line tool provided by Microsoft and is found on all Windows 10 computers. This is a one-by-one process. If you have multiple devices with this problem and need to fix all of them, best to use option number two.

DiskPart Method

To launch DiskPart, simply go to the search function and type DiskPart

You now see the command prompt for DiskPart and type list disk

DiskPart will list all the storage devices connected to your computer. From this list, identify which USB is your problem device. The easiest way to determine this is to check the capacity for the drive listed by DiskPart.

Select the disk you want to change the signature ID for, for example Disk 1, which is the second disk listed (typically disk 0 is your C drive). Type select disk 1

Now that disk one is selected, type uniqueid disk and the utility will spit out the disk signature for disk 1.

Our final step is to change this value. Knowing a hexadecimal value we can use, such as A53AEBE9, type the following in DiskPart: unique disk ID=A53AEBE9 and click Enter.

With this change, you can now go into Disk Management and put the device Online. When the device is online, Windows Explorer will see the device and you can use it. There is no longer a USB disk signature collision.

If your hexadecimal value will not take, it means your MBR file doesn’t have a signature you can change. You will need to flash the device with your bootstrap code. More details on that from a previous article found here.

Another reason why option number two, below, is better is that the hexadecimal number assigned to the partition is automatic and works. There is no guessing on what hexadecimal to assign to the partition, a step you must do in DiskPart.

The second solution is downloading the free Partition Wizard and opening the software. The Partition Wizard software will automatically identify the USB disk signature collision and update the necessary MBR. Super simple!

There is more technical information about disk collision issues from Wikipedia. You can brush up on the details there if so inclined.

Update:

From this article, the Raspberry Pi 4 USB-C power port was designed outside of official USB-IF specifications, making it incompatible with many USB-C chargers and power supplies. You can read more from the link above. The analysis leading to this conclusion was conducted by well-known Google engineer Benson Leung.

The Raspberry Pi is a collection of small computer boards assembled in a simplified way to form the foundation of a computer system. The Raspberry Pi (also known as RPi) was released in February 2012 in the United Kingdom. Its original intent was to provide a low-cost, simple computer platform for students to learn and develop on.

The original model became far more popular than anticipated and quickly expanded beyond its intended educational market into areas such as robotics. The platform does not include peripherals such as keyboards or mice, nor does it ship in a case. It is, quite literally, a bare-bones product.

To give you an idea of its popularity, Raspberry Pi products sold more than 19 million units from their 2012 launch through the end of fiscal year 2018. This places the Raspberry Pi among the best-selling computers in the world, albeit with limited resources. Until now.

This week, the Raspberry Pi Foundation released the Pi 4. It is an impressive upgrade. Here are the key specifications:

• A 1.5GHz quad-core 64-bit ARM Cortex-A72 CPU (~3× performance)
• 1GB, 2GB, or 4GB of LPDDR4 SDRAM
• Full-throughput Gigabit Ethernet
• Dual-band 802.11ac wireless networking
• Bluetooth 5.0
• Two USB 3.0 and two USB 2.0 ports
• Dual-monitor support at resolutions up to 4K
• VideoCore VI graphics supporting OpenGL ES 3.x
• 4Kp60 hardware HEVC video decoding
• Compatibility with earlier Raspberry Pi products

In addition to the hardware improvements, the Raspberry Pi Foundation says the new system includes an extensively modernized user interface, an updated Chromium 74 web browser, and a transition from USB micro-B to USB-C for power. The new connector supports an additional 500mA of current, ensuring a full 1.2A is available for downstream USB devices even under heavy CPU load.

The new boards are available to order now.

In the past, users have attempted running Windows on the Raspberry Pi platform, but performance was predictably slow. With this new configuration, we are curious to hear who has tried it and how it performs. Feel free to share your experience by emailing gmo @ getusb dot info.

Problem: Windows Will Not Assign a Drive Letter to a USB Flash Drive

This issue can occur on Windows 8 and Windows 10. You unplug a USB flash drive, plug it back in, and Windows fails to assign a drive letter. That’s a real problem, especially when every other computer handles the same device without issue.

There are three solutions. All of them can work:

1. You can open Disk Management and manually assign a drive letter to the device. This works, but it’s a repetitive and inconvenient fix if the problem happens often.
2. There’s a good chance the driver or registry entry for that device is corrupt. Use the USBScrub tool to remove old USB registry entries. In many cases, this resolves the issue immediately. Download USBScrub
3. Use DiskPart and enable the automount feature.

• Open Command Prompt as Administrator (search for Command Prompt in the Start menu, right-click, and select “Run as administrator”).
• Type diskpart and press Enter.
• At the DiskPart prompt, type automount enable and press Enter.
• Type exit and press Enter.

For solution number one above, Disk Management is essentially the graphical (GUI) version of DiskPart, but with a reduced feature set compared to what DiskPart can actually do.

DiskPart includes dozens of useful commands for managing storage devices. One of the most important is automount, which controls whether Windows automatically assigns drive letters to newly connected volumes.

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— Coralina Aiazzi (@Cora_Mat) March 21, 2019

We’ve read online that Microsoft’s May 2019 update might not install on systems that have USB flash drives or SD cards connected. According to Microsoft, the update is intentionally blocked when removable storage is detected because the operating system may reassign drive letters during the upgrade process.

At first glance, drive letter reassignment doesn’t sound like a serious issue, especially for removable devices. However, Microsoft also noted that internal hard drives could be affected by this drive letter shuffle.

That’s the red flag.

The newly published Windows 10 support documentation explains that systems already running the April 2018 update (version 1803) or the October 2018 update (version 1809) may receive the error message: “This PC can’t be upgraded to Windows 10.” This happens specifically when USB storage devices or SD cards are detected during the upgrade process.

Microsoft’s documentation does not indicate that internal drives will be reassigned when no removable media is present. That’s why the company chose to block the update entirely if a USB device or SD card is connected. Microsoft understands how critical mounted internal drives are to system stability, so this preventative block is their way of avoiding a potentially serious issue.

In a battle so old most users no longer think about it, Microsoft has moved away from requiring safe removal for USB flash drives. The original intent behind safe removal was to prevent data loss if a user unplugged a drive before an active write operation had completed.

In practice, data loss was uncommon unless a large file was actively being transferred, but it is notable to see Microsoft finally adapt to real-world user behavior.

The update that introduced this change arrived with Windows 10 version 1809. If you are unsure which version of Windows you are running, right-click the Windows icon in the lower-left corner of your screen and select System.

From the resulting screen, you can view the installed version of your operating system.

If you found this post, chances are you are trying to delete the System Volume Information folder from a USB flash drive.

UPDATE:

Thanks to a reader who shared additional details, we now have a solution that works universally across Windows PCs. This approach prevents the recurring message, “There’s a problem with this drive. Scan the drive now to fix it.” To apply the universal fix, scroll to the bottom of this article and look for Updated Solution.

There are several common reasons people want to remove this folder:

• A Smart TV or car stereo displays the folder and uses it as the default playback location.
• A binary or checksum verification utility flags the folder as inconsistent.
• Windows repeatedly shows the “Disk needs to be scanned and repaired” message when a drive is removed without ejecting.
• Antivirus software reports the folder as a potential risk.
• A USB duplication or production workflow is disrupted by the folder.

You can skip ahead to the instructions if you prefer, but understanding what this folder does may help you decide whether removing it makes sense.

Any storage device connected to Windows will contain a System Volume Information folder. It is hidden by default, which is why you may not see it unless hidden files are enabled.

This folder typically contains two files used for restore points and indexing. Windows uses this information to speed up searching and to associate drives with internal search databases.

The files are usually IndexerVolumeGuid and WPSettings.dat. The GUID assigns a unique identifier to the drive so Windows knows which index database to use when the device is reconnected.

The WPSettings.dat file is related to Windows Phone storage settings. On a hard drive this may be useful, but on a USB flash drive it serves little purpose.

If this were a system hard drive, deleting the folder would not be recommended. For removable storage such as USB flash drives, removing it generally carries very little risk.

So how do you remove this folder?

And how do you stop it from coming back?

The process has two parts. First, remove the folder from the drive. Second, configure Windows so it does not recreate the folder in the future.

Connect the USB flash drive to your computer. Open File Explorer, double-click the USB drive letter, type cmd into the address bar, and press Enter.

This opens a command prompt scoped directly to that drive.

At the command prompt, type the following command to remove the folder:

rmdir “system volume information” /s /q

Press Enter. The folder is now removed.

Next, configure Windows so the folder does not return.

Press the Windows key and R together to open the Run dialog. Type gpedit.msc and click OK.

Navigate to Computer Configuration > Administrative Templates > Windows Components > Search.

Locate the policy labeled Do not allow locations on removable drives to be added to libraries and double-click it.

Select Enabled, then click Apply and OK.

To ensure indexing does not restart on reboot, press Windows + R again and type services.msc, then click OK.

Scroll down to Windows Search and double-click it. Set the Startup Type to Disabled, then click Apply and OK.

At this point, the System Volume Information folder has been removed and Windows has been configured not to recreate it, providing a permanent solution for USB flash drives.

HS Code for USB Flash Drives

When importing or exporting USB flash drives in the United States, you will want to use the correct Harmonized System code to complete customs and shipping paperwork accurately.

The Harmonized System code is an international tariff nomenclature that defines standardized names and numbers assigned to traded products. The HS Code system came into effect in 1988 and is maintained by the World Customs Organization (WCO), headquartered in Brussels, Belgium. Today, more than 200 countries participate in and rely on this system.

The HS Code for a USB flash drive is: 8523.51.0000

If your freight forwarder or shipping service indicates that an ECCN is required to ship USB flash drives or to complete Automated Export System (AES) documentation, providing this HS Code should resolve the issue in most cases.

ECCN stands for Export Control Classification Number. An ECCN is an alphanumeric designation used within the Commerce Control List to identify items that may be subject to export control regulations.

Anyone in tech has seen the reports and news about USB sticks with a virus ruining a company network or infecting computers. Google built a small and effective feature: Chromebook Gets a USB Guard.

The USBGuard is a feature that blocks interaction between the mass storage device and the Chrome operating system. The OS will give power to the device, but not let data transmit.

The USBGuard blocks this activity when the Chromebook is in locked mode. When the Chromebook is not in lock mode, the USB will interact as expected as a read/write device.