Computer Support Blog

How to Fix Error Code 0x800704ec when turning on Windows Defender

The most common reason for 0x800704ec to pop up on Windows 10 is due to the installed anti-virus program. Initially, Windows Defender used to be called Microsoft Security Essentials and was a downloadable program for Windows XP, and later was included with Windows Vista and Windows 7. Since Windows 8 came out, the software evolved into a built-in anti-malware application, which is set to run in the background of the system all the time. This post will walk you through 5 solutions to solve this Windows Defender problem.

The error code 0x800704ec may occur when you are turning on the Windows Defender. This is not really a problem as the software and the operating system have been intentionally designed in this manner.

About Error Code 0x800704ec

The error code 0x80004ec is a Windows Defender error, occurring when you are turning on it. When this error occurs, you will see the warning message This program is blocked by group policy.

For more information, contact your system administrator. (Error Code: 0x800704ec), as shown in the following picture:


Then you may wonder what may cause the Windows Defender error code 0x800704ec. As a matter of fact, there are many reasons causing the Windows error code 0x800704ec. For example:

  • Third-party antivirus software.
  • A corrupted Group policy.
  • Damaged Registry files.

In general, the three reasons are the most common one to cause Windows Defender error 0x800704ec. Meanwhile, it also may be caused by other reasons.

Meanwhile, do you know how to fix error code 0x800704ec?

Thus, in the following section, we will walk you through 5 solutions to solve the error code 0x800407ec. If you have the same problem, try these solutions.

Method 1. Enable Windows Defender Services

1. Open Services Window

2. Enable Windows Defender Services

When you have enabled all Windows Defender services, reboot your computer and run Windows Defender again to check whether the Windows Defender error code 0x800704ec is solved.

Method 2. Uninstall or Disable Third-Party Antivirus Software

1. Open Control Panel

2. Uninstall the third-party antivirus software

When you have completed all steps, you can run Windows Defender again to check whether the error code 0x800704ec is solved.

Besides uninstalling the third-party antivirus software, you can also choose to disable it. Thus, you can click here to know more.

Method 3. Use Registry Editor

1. Open Registry Editor

2. Change Value data

You can reboot your computer and run Windows Defender again after all steps finished to check whether the error code 0x800704ec is solved.

Method 5. Optimize the System

In general, the damaged or corrupted system files may also lead to the error code 0x800704ec. So if you encounter this Windows Defender error, it is advisable to check and fix the corrupted system files by running System File Checker and DISM tool.

Step 1: Open Command Prompt

  1. Type command prompt in the search box of Windows 10 and choose the best-matched one.
  2. Right-click it to choose Run as administrator to continue.

Step 2: Type the command

  1. In the command line window, type the command sfc /scannow and hit Enter to continue.
  2. The scanning process will take a few minutes. So, please do not close the command line window until you see the message verification 100% completed.


When the process is finished, reboot your computer and run Windows Defender again to check whether this Windows Defender error is solved.

If you still encounter the issue error code: 0x800704ec, you may need to run some advanced commands to optimize your system and system files.

Then just input the following commands one by one. Please hit Enter after each command.

  • DISM.exe /Online /Cleanup-image /Scanhealth
  • DISM.exe /Online /Cleanup-image /Restorehealth

When the whole process is finished, you can close the command line window and reboot your computer and run Windows Defender again to check whether the error code 0x800704ec is solved.

In general, after you have tried the above solution, the error code 0x800704ec can be solved. If none of the above solutions is working, you may need to reinstall the operating system to solve the Windows Defender error.

Apart from methods mentioned about, you can also use other methods to fix 0x800704ec error, such as changing the settings of Group Policy.

A Quick Reminder

As is well known, the Windows Defender is a critical program of Windows since it can effectively protect your computer and files against virus attack. But from this post, you can learn that the Windows Defender may fail to work due to some reasons.

In addition, if the Windows Defender failed to work, your computer will be in high risk of danger since it would be easily attacked by the virus.

On the one hand, you may also encounter other problems besides the Windows Defender error 0x800704ec. So in order to protect your computer and data, you had better create a system image.

Thus, in order to create a system image, you can take advantage of a piece of professional backup software. Here, MiniTool ShadowMaker is strongly recommended.

MiniTool ShadowMaker is designed to back up the operating system, disk, partition, files and folders. And it is a piece of file sync software to sync files to two or more locations.

So, in order to back up the operating system, MiniTool ShadowMaker is the best choice. Just click the following button to get MiniTool ShadowMaker Trial to have a try to choose to purchase an advanced edition.

In the following section, I will show you how to back up the computer with the step-by-step guide.

Step 1: Launch MiniTool ShadowMaker

  1. Download MiniTool ShadowMaker and install it on the computer.
  2. Launch it.
  3. Click Keep Trial to continue.
  4. Choose Connect in This Computer to continue.


Step 2: Select backup source

  1. After launching MiniTool ShadowMaker, please go to the Backup page.
  2. Click Source module to continue.
  3. In the pop-up window, choose Disks and Partitions.
  4. Select the system disk and click OK to continue.


Step 3: Select the backup destination

  1. Click the Destination module.
  2. There are five available paths including the AdministratorLibrariesComputerNetwork and Shared folders.
  3. You can choose a destination to save the backup images and click OK to continue. It is recommended to choose an external hard drive.


Here, there are three important points where you should pay attention to.

  • MiniTool ShadowMaker enables you to create an automatic backup. Just click Schedule to continue.
  • MiniTool ShadowMaker offers three different backup schemes. The Incremental Backup is chosen by default. You can also change it through the Scheme button. 
  • You can set some advanced backup parameters through Options.

Step 4: Start to back up the operating system

  1. After you have selected the backup source and destination, you can click Back up Now to perform the task immediately.
  2. You can also click Back up Later to delay the task and restart it in the Manage page.

In addition, you can also choose to create the bootable media which can be used to boot your computer and enter MiniTool Recovery Environment to do some recovery solutions.

When all steps are finished, you have successfully created a backup image. This way can effectively protect your computer even though the Windows Defender fails to work.

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