“Windows Security threat service has stopped restart it now” is a common issue. If you are hit by this unexpected error in Windows 10/11, what should you do to get out of the trouble? Take it easy and you can find some effective solutions from this post on the MiniTool website.

Threat Service Has Stopped Restart It Now Windows 10/11

Windows Defender, also called Windows Security, is a powerful antivirus program that is built in Windows 10 and 11. It can help to scan the entire operating system and protect the PC against malware and viruses in real-time.

However, sometimes this antivirus software doesn’t function properly and you may run into some common issues, for example, Windows Defender not turning on, Windows Security not working, Windows Defender Offline Scan not working, and more. If you encounter one of these issues, click the given link to find solutions.

Besides, you may be hit by another common unexpected error - threat service has stopped restart it now. This is the topic that we will discuss today.

When trying to launch this antivirus program, you may see this error message. If you click the Restart now button, the service starts and the error disappears. That’s good. However, if not, another error occurs on the computer screen saying “Unexpected error. Sorry, we ran into a problem. Please try again”.

Windows Defender threat service has stopped restart it now

Well then, how can you get rid of the trouble? Don’t feel vexed since you can easily fix this error after trying the methods below.

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Fixes for Threat Service Has Stopped Restart It Now

Enable Windows Defender Services in Services

To run Windows Defender or Windows Security, the related services should be running. Or else, you may get the error “Threat service has stopped. Restart it now” in Windows 11/10. The following is how to enable these services in the Services window:

Step 1: Open the services management console by typing services.msc in the search box and clicking Services. Or you can press Win + R, type services.msc and click OK.

Step 2: Locate the following services and make sure the startup type of these services is set to the default values:

  • Windows Defender Advanced Threat Protection Service – Manual
  • Windows Defender Antivirus Network Inspection Service – Manual
  • Windows Defender Antivirus Service – Manual
  • Windows Defender Firewall Service - Automatic

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If any service is stopped, start it. Just double-click on it and choose Start. To change the startup type, double-click on one service and choose the correct option from the drop-down menu in Startup type.

start Windows Defender Advanced Threat Protection Service

Edit Windows Registry

If the above fix cannot work to remove “threat service has stopped restart it now”, you can try to enable Windows Defender services in Windows Registry.

Before you proceed with the modification of the Windows Registry, it is recommended to back up your registry items since mistaken operations may cause the system to go wrong. To do this work, follow the guide - How to Back up Individual Registry Keys Windows 10/11.

See how to do this task:

Step 1: Launch Windows Registry Editor by clicking Win + R, typing regedit to the text box, and clicking OK. Or, type regedit to the search box in Windows 10/11 and click the result to open this editor.

Step 2: Click Yes in the User Account Control window to continue.

Step 3: Navigate to this path step by step: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender. Or you can copy & paste the path to the address bar and press Enter.

Step 4: If you see the two items – DisableAntiVirus and DisableAntiSpyware in the right pane, double-click on each one and set the value data to 0.

If these two items are not displayed, create them: right-click on the empty space and choose New > DWORD (32-bit) Value. Give a name to one. Then, change the value data of each item to 0.

DisableAntiSpyware in registry

Step 5: Close Registry Editor and restart your Windows PC. Then, go to run Windows Defender to see if the issue is solved.

Besides, there is another thing you can have a shot.

Step 1: Go to the path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend.

Step 2: In the right pane, double-click on the Start item and change its value data to 2 from 4.

If your PC misses some required services like WinDefend and SecurityHealthService, you cannot see them in this path HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services. To fix “Windows Security threat service has stopped restart it now”, try the next method.

Export the Missing Security Service from Another PC

Make sure the system version of the Windows PC you will export the security services from is the same as yours. Besides, prepare a USB flash drive and connect it to another PC.

Step 1: Go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services, right-click on SecurityHealthService or WinDefend and choose Export to export the file to your USB drive. Then, name the file as SecurityHealthService or WinDefend.

export missing security services in Registry

Step 2: Eject the USB drive from the PC and plug it into your computer.

Step 3: Copy the exported registry file to your desktop from the USB drive and double-click on it to merge it to Windows Registry.

Step 4: Restart the PC and see if the issue – Windows Security threat service has stopped restart it now is fixed.

Uninstall Third-Party Antivirus

Sometimes “Threat service has stopped. Restart it now” is only an informational message. If you install any third-party antivirus program on your Windows 10/11 PC, Windows Defender will stop working automatically and shows you the message. Go to uninstall this software since it can interfere with Windows Security/Windows Defender.

Just go to Control Panel and click Uninstall a program from the Program category. Right-click on the antivirus program and click Uninstall.

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Run SFC and DISM

Sometimes “threat service has stopped restart it now unexpected error” is caused by missing or corrupted system files. So, you can try to run an SFC and DISM scan to check for the entire operating system and repair corruption to fix some issues like the Windows Security issue.

Step 1: Type command prompt in the search box in Windows 10/11 and click Run as administrator from the right pane.

Step 2: Type sfc /scannow and press Enter to begin verification.

Windows 10 sfc scannow

Sometimes System File Checker fails to scan and it may get stuck at verification. If you are hit by this issue, go to find solutions from this related article - Windows 10 SFC /Scannow Stuck at 4/5/30/40/73, etc.? Try 7 Ways.

Step 3: After finishing the SFC scan, type Dism.exe /Online /Cleanup-Image /Restorehealth to the CMD window and press Enter. This process will take a few minutes and wait patiently.

Repair Windows 10/11 via an In-Place Upgrade

Another solution to fix the Windows Defender issue is to perform an in-place upgrade and you can also have a shot. Before you upgrade this PC, it is recommended to back up your important data and create a system image to avoid something wrong.

To do this task, we strongly recommend using MiniTool ShadowMaker, a professional PC backup software for Windows 11/10/8/7. It can be used to back up files, folders, systems, disks, and partitions. This program can meet your requirements well. It is free to use to enjoy all the features in 30 days. Just click the following button to download it.

Free Download

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Step 1: After downloading MiniTool ShadowMaker Trial Edition, double-click on the icon to launch it on your PC.

Step 2: Move to the Backup tab, you can find this software backs up the system by default since all the system-related partitions are selected as the backup source. If you want to back up data, go to Source > Folders and Files, check the items you want to back up, and click OK.

Step 3: Go to Destination and choose a path to save the backup. An external hard drive or a USB flash drive is recommended.

Step 4: Click the Back up Now button to execute this task at once.

MiniTool ShadowMaker system backup

Next, it is time to perform an in-place upgrade to fix “threat service has stopped restart it now”. See the guide below to know how to do this work.

To repair your Windows 10/11 via the upgrade, you need to ask Media Creation Tool for help and here we take Windows 10 as an example.

Step 1: Go to the Download Windows 10 page from Microsoft and download Windows 10 Media Creation Tool by clicking the Download tool now button.

Step 2: Double-click on the exe file on your PC and click Yes in the User Account Control interface.

Step 3: After a few things are ready, click the Accept button to agree to applicable notices and license terms.

Step 4: Check the option of Upgrade this PC now and click Next to go on.

upgrade this PC via Media Creation Tool

If you need to create a bootable USB drive or download an ISO file of Windows 10, tick the option of Create installation media (USB flash drive, DVD, or ISO files) for another PC.

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Step 5: This tool is downloading Windows 10 and this can take a few minutes. During the process, you can feel free to keep using your PC.

Step 6: This tool is checking for updates and wait patiently.

Step 7: When everything is ready, click the Install button to start installing Windows 10.

If you want to keep other things during the installation, click Change what to keep and select the corresponding option.

install Windows 10 via Setup

If you are running Windows 11 and need to perform an in-place upgrade, refer to this post to find what you should do - How to Perform a Windows 11 In-Place Upgrade.

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After finishing the update, now you can try to run Windows Defender or Windows Security and the issue should be removed.

Tips to Protect Your PC

Only running Windows Defender is not enough to keep your PC secure and you can find why from our previous post - Is Windows Defender Enough? More Solutions to Protect PC. To make sure your computer is safe and avoid some threats, there are some things you should do:

  1. Don’t Open Emails from Unfamiliar Users
  2. Turn on SmartScreen Filter
  3. Turn on User Account Control (UAC)
  4. Don’t Visit Suspect Websites
  5. Don’t Install Cracked Software
  6. Pay Attention to Your Downloaded Files
  7. Strengthen Your Internet Browser Security Settings
  8. More…

To find details, read our previous post - How to Protect Your Computer from Viruses? (12 Methods).

Final Words

“Threat service has stopped restart it now” is a common issue on Windows 10/11. If your PC confronts this annoying problem, try the solutions above one by one and you should easily get rid of the trouble. If you find some other methods to help you out, you can write it in the comment below.

Besides, after fixing the issue, we strongly recommend backing up your PC to keep the machine safe. In addition, try some other reliable ways to protect your PC against viruses and malicious programs since Windows Defender is not enough to keep the PC safe.

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