Windows Errors

Fix Windows Defender won’t Start in Windows 10

Fix Windows Defender won’t Start in Windows 10

Viruses and malware in a Windows 10 PC can be quite dangerous. Such files can cause a lot of issues in your computer including corrupting all of your important data. Not only that but things like ransomware can even lock down your computer until you pay money to the owner of that ransomware. In order to protect your computer from such threats, an anti-virus software is always recommended. While there are a lot of such software available out there, Windows 10 has one already built-in which is called Windows Defender. And today, we are taking a look at an error related to it. We will learn how to Fix Windows Defender won’t Start in Windows 10 error in this article. You will find all of the possible fixes in order to fix this issue:

What is Windows Defender and its Importance

Windows Defender is a very useful service or application which is present in all Windows 10 computer. As the name suggests, it defends your computer from infected files. Not only you can use it to scan existing files in your computer, but it also actively scans for infected files at all times. This means that as soon as an infected file enters your computer, Windows Defender will safely remove it. And the best part about Windows Defender is that it starts right when you boot your computer.

How to Fix Windows Defender won’t Start in Windows 10

Even though Windows Defender is supposed to launch by itself, some users experience an issue where Windows Defender does not start. This can be very dangerous for your Windows 10 PC as it is vulnerable to infected files. Such an issue can be caused due to things like changed windows settings, corrupted system files, improper Windows update, and more. So, to successfully fix the issue with Windows Defender, make sure to go through all of the given solutions one by one:

Solution 1: Enable Real-time Protection in Windows 10

Windows 10 has an option built in which can be used to either enable or disable Windows Defender. And if you have disabled this option accidentally, Windows Defender won’t start. In such a case you have to go to system settings in Windows 10. And make sure that Real-time protection is turned on. You can enable this option in Windows 10 by following these steps one by one:

  • Use Windows Search to search for Windows Defender Settings and open it.


  • In here, click on Virus & threat protection and choose the manage settings option under Virus & threat protection in the newly opened window.

  • Finally, make sure that the Real-time Protection option is enabled in here. This will ensure that Windows Defender isn’t having issues due to any Windows settings.

Solution 2: Fix Date and Time in Windows 10

If your computer has the wrong date and time, it might cause issues with Windows Defender. Since the Windows Defender uses the internet to check for the latest threats out there, having a wrong date and time can cause interference with this process. This can result in an issue where Windows Defender won’t start in Windows 10. You can easily fix this issue in Windows 10 by simply fixing the date and time of your PC as shown here:

  • First, right-click on the time in the bottom right corner of your screen.



  • Select Adjust date/time from this list which will open a new window.
  • In here, enable the set the time automatically and set the time zone automatically options. Doing so will automatically fix the time and date of your Windows 10 computer.

Solution : Scan and Fix Corrupted System Files in Windows 10

In case the system files in your computer are corrupted, you might face issues on your computer. To get rid of such corrupted system files, Windows 10 has an inbuilt feature. This feature allows the user to scan for corrupted system files and fix them. The whole process of scanning and fixing system files is done via the Command Prompt. In order to fix Windows Defender by fixing system files, follow these instructions:

  1. Press Windows Key + R on your keyboard to open Run. In here type cmd and press enter to open the command prompt.

  2. Now, type sfc /scannow and press enter. Doing so will run an initial system file scan.



  1. Once that process is done, enter the following commands one by one and press enter.
    • Dism /Online /Cleanup-Image /CheckHealth
    • Dism /Online /Cleanup-Image /ScanHealth
    • Dism /Online /Cleanup-Image /RestoreHealth
  • At last, reboot your computer which will fix any issues with Windows Defender.



Solution 4: Restart Security Center Service in Windows 10

The Windows Defender in Windows 10 uses a number of services for proper functioning. One of the most important services used by Windows Defender is called Security Center. And if this service is having issues, you might face the Windows Defender won’t start problem on your computer. To fix any issues with the Security Center service you can simply restart this service in Windows 10. This can be done via the Services utility as shown in the following step by step guide:

  • Using Windows Search, open Services as shown here.

  • Now, in the list of services, look for Security Center.

  • After that, right-click on it and select Restart which will restart the Security Center service.
  • Finally, reboot your computer after this which will successfully start Windows Defender on boot.

Solution 5: Disable all other Anti-virus Software

Windows Defender might be having an issue in Windows 10 if you have installed other Anti-virus in your computer. Because whenever you install an anti-virus software, it will simply disable Windows Defender. And even if you try to manually launch it, it won’t work. Therefore, if you want to fix the Windows Defender, make sure uninstall or disable all other anti-virus software in Windows 10.

We hope that you’ve successfully fixed the Windows Defender won’t Start error in your Windows 10 PC. We are pretty sure that at least one of the fixed mentioned above has worked for you and you’re not facing the Windows Defender error on your computer. In case you liked this article, then make sure to share it on social media. If you have any doubts regarding any of the solutions, feel free to ask any queries in the comments section below.

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