By Emily / Last Updated October 12, 2019

Reasons of formatting C drive in Windows PC

In general, C drive is usually the partition that holds OS, booting files like boot.ini, bootmgr, bcd, etc. on most computers, and formatting C drive means deleting operating system and other related crucial information on it. As a result, Windows will stop working. Why do users still want to format C drive using Command Prompt? Here are some common reasons:

  • Upgrade system disk: Windows is installed on traditional mechanical hard disk drive (HDD), so you want to upgrade the system HDD to SSD for better performance.

  • Reinstall OS: operating system on your computer has crashed and cannot boot. In this case, you can format C drive and reinstall system.

  • Replace computer: when your computer is failing and needs to be replaced with a new one, you had better format C drive to erase data before selling or donating in view of data security.

  • Eliminate virus and malware: Windows OS is always the focus target of virus and malware. Once it is infected, personal data or files will be dangerous. Formatting C drive can help remove virus and protect computer.

Failed to format C drive in File Explorer

“I have an Acer 5101 laptop with 2 drives. I have bought Windows 7. I managed to install this on the D drive having reformatted it before. Now I wish to do the same on the C drive. When I try to format it, I receive the message "You cannot format this volume. It contains the version of Windows that you are using…”. Any ideas?”

Cannot Format C Drive

On Windows computer, you can format any partition except the system C partition in File Explorer or Disk Management when the OS is running. When you try to format C drive in File Explorer, you will receive the above error message.

That’s because Windows sets this limitation out of security consideration to prevent users from deleting system by mistake. In one word, this partition cannot be formatted or deleted within Windows.

How to successfully format C drive using Command Prompt? (Windows Setup CD required)

Though you cannot format C drive within Windows like you format other drives, you can format C drive outside of Windows. To do that, you need to boot your computer from the Windows setup media (CD, DVD or bootable USB device), and use the Command Prompt to format C drive. Specific steps are listed as below:

Importance: because formatting will delete everything on the C drive, you can first back up system drive if necessary.

Step 1. Insert Windows installation media into the (Windows 10/8/7) computer and enter BIOS to set computer boot from it.

Step 2. In the pop-up window, select “Language to install”, “Time and currency format” and “Keyboard or input method”. Then, click “Next”

Step 3. On the next window, click “Repair your computer” from the lower-left corner.

Step 4. In the “Choose an option” window, click “Troubleshoot”> “Advanced options” in the next Window.

Step 5. When the “Advanced options” window appears, select “Command Prompt”.

Command Prompt

Step 6. In the Command Prompt window, type “format c: /fs:ntfs” and hit “Enter”.

Format C Drive Command Prompt

Or you can click “Install now” in the above step 3 to enter the screen of “Install Windows” where you can select C (primary) drive and click “Format” to format C drive.

Format C Drive

Can we format C drive without Windows Setup CD?

As demonstrated in the last part, we can know that format C drive through Command Prompt requires the usage of Windows installation CD. But what if you don’t have one?

In this situation, you can switch to AOMEI Partition Assistant Standard. With it, you can first make a bootable USB, boot your computer from it to enter WinPE environment, and then format C drive easily. You just need to prepare a USB device (min 8GB). Then take the steps:

Tip: creating a PE bootable USB drive will delete everything on the selected USB, so back up files you require in advance.

Step 1. Connect the USB drive to your Windows computer, and free download AOMEI Partition Assistant. Install and launch it on PC.

Step 2. In the main interface, click “Make Bootable Media”.

Make Bootable Media

Step 3. Choose the USB drive and click “Proceed”.

Choose Usb Drive

Step 4. Wait for the process to complete. The created bootable USB drive will contain the pre-installed AOMEI Partition Assistant Standard.

Step 5. Restart the computer and enter BIOS to change boot order, so that this computer will boot from the USB device.

Note: If you do not know how to enter BIOS or change boot sequence, you can ask help from the motherboard tech support. Once your computer boots from the bootable disk successfully, AOMEI Partition Assistant Standard will be launched automatically.

Step 6. In the main interface of AOMEI Partition Assistant, right-click the C partition and select “Format Partition”.

Format C Drive

Step 7. In the pop-out mini window, you can select a proper file system for your needs and click “OK”.

Choose File System

Step 8. Hit on “Apply” and “Proceed” to commit the pending operation.

Apply

Apart from formatting C drive without using Windows installation media, AOMEI Partition Assistant Standard permits you to delete system partition within Windows. That is to say, you can skip the steps of creating Windows PE bootable media above as well.

Summary

We have talked about how to format C drive via Command Prompt by using Windows Setup CD, as well as introduced how to format system partition without CD. Hopefully, you can get necessary information on this page.

If you format C drive with the purpose of upgrading to a larger disk, you can upgrade to AOMEI Partition Assistant Professional, which allows you to clone the system disk to larger SSD or HDD while ensures you can boot from the cloned hard drive successfully. Besides, it also comes with many other fantastic functions such as extending system partition, converting system disk between MBR and GPT, and more.