The clean function in DiskPart is a command used to remove all partitions or volumes from a disk, essentially wiping out all existing data on the disk. When you use clean in DiskPart on a particular disk, it performs the following actions:

Removal of partitions: Deletes all partition or volume structures from the selected disk. This includes removing any partition tables and file system information — or said another way, it removes the format of the drive.

Data erasure: The clean command deletes the partition table entries and boot code, but it does not overwrite the data itself. That means after using clean, data recovery software could still potentially recover the original files.

Disk initialization: After executing clean, the disk is left uninitialized. It will appear as raw, unallocated space. To use the drive again, you must open Windows Disk Management and create a new volume. Once that is done, the device will have a file system and be usable again.

The CLEAN function is a practical way to quickly remove partitions and start fresh. For example, if you write a 5GB IMG file to a 32GB USB drive, the drive will often appear as only 5GB usable. The remaining space becomes unallocated. Running the DiskPart CLEAN command resets the device so that, after reinitializing in Disk Management, the full 32GB capacity is available again.

The clean all function in DiskPart is similar to clean but adds an additional step of overwriting the entire disk with zeros. When you use clean all, DiskPart performs the following actions:

Removal of partitions: Like clean, clean all deletes all partition or volume structures from the selected disk, removing existing partition tables, file systems, and metadata.

Data overwriting: In addition to removing partitions, clean all writes zeros to every sector of the disk. This effectively erases all data and makes recovery extremely difficult using standard recovery tools.

Disk initialization: After executing clean all, the disk is left completely wiped and uninitialized. It appears as raw, unallocated space with no recoverable structure.

The clean all command is a more secure method of erasing data than clean, because it actively overwrites every sector. The tradeoff is time — it can take significantly longer to complete, especially on large drives.

Tip: As with clean, always double-check that you have selected the correct disk before running clean all. Running this command on the wrong drive results in permanent data loss.

Ref: DiskPart on Wikipedia

Below are a list of the ten most common questions about a disk signature collision along with the related answer. The bottom of this article includes a video for some of the diskpart steps, which is needed when investigating a disk signature collision.

1. What is a disk signature collision?
2. Why does Windows create a disk signature collision?
3. How do I find the disk signature ID?
4. Does Windows 10 have diskpart?
5. How do I start or launch diskpart?
6. How to change a disk signature?
7. Is there a disk signature collision for every device?
8. What is MBR verse GPT
9. What is the difference between an online and offline device, how do I fix it?
10. Where can I find the full list of diskpart commands?
11. Jump right to the demonstration video at bottom of article

#1 – What is a disk signature collision?

When two (or more) storage devices have the same hexadecimal value for their disk ID (also known as disk signature). Windows does not like to see multiple storage devices with the same signature, so it will take all but one offline so the user gains access to only one device. The signature collision is most often found when binary copies of a master have been made to target devices.

#2 – Why does Windows create a disk signature collision?

Our understanding of why Microsoft did this was to prevent malware from spoofing the OS by presenting an identical seeming drive with bad intent. Bear in mind this MBR stuff was developed when dinosaurs still ruled the earth. Malware was but a dream in some teenage miscreants mind. So little effort was expended in that direction, much to the chagrin of todays Microsoft. The bible says something about this, “The sins of a father shall be visited upon their sons” or words to that effect.

#3 – How do I find the disk signature ID?

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.