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 in forums and How To’s for years when someone is explaining what to do with USB flash drives. I think most people glaze over the definitions of Clean, Erase and Format simply because they believe the terms are interchangeable, or they aren’t planning on doing the task mentioned in the post.

I hope the following information will clear up some terms and definitions so we can all better understand what people are talking about when passing along information about flash drives and the Clean, Erase and Format function.

All of these functions can be performed in your Windows 10 computer, or higher. I will start with the least complicated definition and task, and move along from there.

Format

This function is what 98% of Windows computer operators will use. This is the graphical interface inside Windows when you right click a drive letter and ask the operating system to format the drive. What is this function really doing?

Format is the least complicated of the tasks, and this function is removing the File Allocation Table of the USB and creating a new one. Said a simpler way… this function takes away the list of files sitting on the drive so it then appears blank with no data.

It’s important to note, the files are still on the drive, just not listed in an easy, organized manor which you can see through windows explorer (clicking on the drive letter to see the list of files).

Using the most basic file recovery software tools, like the one we wrote about several months back, you can recover all the files sitting on the drive.

Maybe a picture will help. Looking at the image below you can see the “data” is light grey. Meaning the data is still there, just not easily accessible. This data is what recovery software will look for, find, and list back on your drive. Also notice the boot code of the USB (if you want to load an operating system on your USB stick) isn’t touched either.

You might have questions if a USB flash drive should be formatted as FAT, FAT32, exFAT or NTFS and we did a great post about that a bit earlier as well.

Clean

The Clean function is a bit more in-depth than the format function. This function applies directly to the Master Boot Record (MBR) or boot code mentioned just above.

The Clean function will clear out boot code and will remove any partition on the flash drive. The partition of a flash drive is the information which tells a host computer how big the drive is, and if the partition should be bootable in the event you are trying to start the computer from a flash drive.

The Clean function is not accessible through the GUI of Windows, for example you cannot right click on a drive letter and find the Clean function. The Clean function is only accessible through the Windows utility called DiskPart.