[Fixed] Windows Cannot Delete the Active System Partition on This Disk 

This passage will help you figure out the reasons and give you several solutions to why Windows cannot delete the active system partition on this disk. 

When you are using Disk Management to delete your partition, you may receive a message: "Windows cannot delete the active system partition on this disk." Here is a typical case of this situation: 

If you are also looking for another way to solve this problem, this article will provide you with different ways to solve the "Windows cannot delete the active system partition on this disk" problem on single or dual systems.

Why Windows Cannot Delete the Active System Partition on This Disk?

Before we start, we need to know why Windows cannot delete the active system partition on this disk. 

The active system partition belongs to the primary partition that can be used to boot the operating system. Here is the definition from Wikipedia:

Usually, the system partition is not suggested to be deleted. Because it may impair the normal operation of the computer and cause the computer to fail to boot. And the active partition belongs to the primary partition, which is also the partition that the system will boot to. So, Disk Management will not allow Windows to delete the active system partition.

Windows Cannot Delete the Active System Partition on This Disk Solutions

Although Windows does not allow you to delete active system partitions. There are two situations where you may still need to delete it:

1. There is only one system on the PC. You want to reinstall the new operating system, so you need to erase the original system first.

2. There are two operating systems on the PC. So, you want to delete the partition you don't need or delete the active system partition to free up storage space and gain unallocated space.

Case 1: Delete Active System Partition in Single System 

For case one, there are three solutions:

Fix 1. Use EaseUS Partition Master

Fix 2. Run Diskpart Command

Fix 3. Use Windows Installation Disc

Let's look at the steps one by one to fix Windows cannot delete the active system on this disk. 

Fix 1. Use EaseUS Partition Master

You need to enter the Win-PE environment by creating a bootable media to delete system partitions in a single system. I highly recommend EaseUS Partition Master, an easy-to-use but powerful tool for managing disks and partitions. 

Here are the steps to fix "Windows cannot delete the active system partition on this disk."

Guide 1. Create Bootable Media

You need to create a bootable disk or DVD/CD to enter the operating system. You can follow the steps.

Step 1. To create a bootable disk of EaseUS Partition Master, you should prepare a storage media, like a USB drive, flash drive or a CD/DVD disc. Then, correctly connect the drive to your computer.

Step 2. Launch EaseUS Partition Master, and find the "Bootable Media" feature on the left. Click on it.

Step 3. You can choose the USB or CD/DVD when the drive is available. However, if you do not have a storage device at hand, you can also save the ISO file to a local drive, and later burn it to a storage media. Once made the option, click the "Create" button to begin.

• Check the Warning message and click "Yes".

Step 4. When the process finishes, you'll see a pop up window, asking if you want to restart computer from the bootable USB.

• Reboot Now: it means you want to restart the current PC and enter EaseUS Bootable Media to manage your disk partitions without OS.
• Done: it means you don't want to restart the current PC but to use the bootable USB on a new PC.

Note: To use the bootable disk on a new PC, you need to resart the target computer and press F2/F8/Del key to enter BIOS, and set the USB bootable disk as the first boot disk.

Wait patitiently and your computer will automatically boot up from the USB bootable media and enter EaseUS WinPE desktop.

Guide 2. Restart the Computer from the Bootable USB

Step 1. Restart the computer and long-press "F2," "F8," or "Delete" to enter BIOS. (Which button depends on your computer)

Step 2. In BOIS, start the computer from the bootable USB.

Guide 3. Delete Partition 

Then, you will enter the page of EaseUS Partition Master. And you need to click it to begin deleting the disk's active system. 

Note that this will delete all existing partitions on the system disk, including the OS. So make sure you've backed up all essential content in advance.

Step 1. Launch EaseUS Partition Master, go to the Partition Manager section, right-click your OS disk and select "Delete All".

Step 2. Click "Yes" ton confirm that you are sure to delete all partitions on the OS disk.

Step 3. Click "Execute * Task" and click "Apply" to start deleting all partitions with OS on the selected disk.

Note: After this, you'll just need to wait patiently and EaseUS Partition Master will automatically delete the OS drive and other data partition on your disk.

Fix 2. Run Diskpart Command 

Using the Diskpart command is also a method that may work. You can try the following steps to delete the Windows active partition.

Step 1. Open a cmd window and run it as administrator.

Step 2. Type diskpart.

Step 3. Type list disk to see all disks.

Step 4. Type select disk n to display the disk numbers that contain the active system partition.

Step 5. Type list volume to see the status and information about the system partition.

Step 6. Enter select volume n.

Step 7. Type delete volume to delete the system volume.

Fix 3. Use Windows Installation Disc

If Windows cannot delete the active system partition on this disk, you can use the Windows installation disk to finish this task. It is also easy to operate with the following steps. 

Step 1. Connect a Windows installation disc to the computer.

Step 2. Choose the language, time, and keyboard method.

Step 3. Click "Install Now."

Step 4. Accept the terms of the license and click "Next."

Step 5. Choose the custom or advanced installation type.

Step 6. Select the system partition and click "Delete."

After these steps, you can easily delete the system partition and install the new system. 

Case 2: Delete Active System Partition in Dual System

For case two, there are two situations:

Situation 1. Two OS on Two Different Hard Drives 

Situation 2. Two OS on One Hard Drive 

I have given two solutions for the two cases. Let's check the detailed steps to fix Windows cannot delete the active system on this disk. 

Situation 1. Two OS on Two Different Hard Drives 

You may also have two operating systems if you have two different hard drives. One is partition C on disk 0, and the other operating system is partition F on disk 1. You need to use the third-party tool to delete the system partition. You can download EaseUS Partition Master.

And follow the steps of Fix 1. Use EaseUS Partition Master

Situation 2. Two OS on One Hard Drive 

If there exist two operating systems on the same hard drive, it may be caused by a system reserved partition.

1. There Is System Reserved Partition

A system reserved partition may exist at the beginning of the disk. If you have two operating systems, the boot files of both operating systems will be saved to the system reserved partition. It is active by default. You can follow the link if you want to delete a system reserved partition. 

2. There Is No System Reserved Partition

If there is no system reserved partition, but there are two systems, you will need to set the system partition you use to active. You can follow the steps below to restart your computer from the bootable CD, delete the partition, and then set it to active. 

Guide 1. Delete Partition via EaseUS Partition Master

Guide 2. Set Active 

Step 1. Run EaseUS partition manager software. On the disk map, right-click the target partition and choose "Advanced".

Step 2. Then, select "Set Active" from the drop-down menu. Click "Yes".  And choose "Execute 1 Task(s)" and click "Apply".

Conclusion 

This article explains why you cannot delete the active system partition. And this guide gives a detailed solution for Windows cannot delete the active system partition on this disk. EaseUS Partition Master is the best way to solve the problem, whether you have a single or dual system. It can create bootable disks, delete partitions, and set the system to an active state.

FAQs About Windows Cannot Delete the Active System Partition on This Disk

Here are some frequently asked questions about deleting partitions. If you're interested, keep reading.

1. How do I delete an active partition?

You can use EaseUS Partition Master to create a bootable disc and then delete the system partition. And Diskpart command is another efficient way.

2. What happens if you delete an active partition?

Usually, you cannot delete the active partition because the active partition is used to boot your computer. If you delete it, all the data and operating systems will be removed.

3. Can I delete the system partition?

You can't delete system partitions with Disk Management on Windows. But you can delete the system partition via EaseUS Partition. You can follow the steps in this passage to delete it.