修复无法打开Windows Defender的问题
Fix Unable to turn on Windows Defender: Windows Defender is an inbuilt antimalware tool that detects virus and malware on your system. However, there are some instances when users experience that they are unable to turn on Windows Defender in Windows. What could be the reasons behind this problem? There are many users who explored that installing any third party antimalware software cause this problem.
Also, if you go to Settings > Update & Security > Windows Defender then you will see that the Real-time protection in Windows Defender is turned on but it’s greyed out and also everything else is turned off and you can’t do anything about these settings. Sometimes the main issue is that if you have installed a 3rd party Antivirus service then Windows Defender will shut itself off automatically. No matter what reasons are behind this problem, we will walk you through the methods to solve this problem.
Why can’t I turn on my Windows Defender?
One thing we need to understand that Windows Defender provides complete protection to our system. Therefore, not able to turn on this feature could be a serious problem. There are many reasons for you not being able to turn on Windows Defender in Windows 10 such as third-party Antivirus might be interfering, Windows Defender is turned off by group policy, incorrect date/time issue, etc. Anyway, without wasting any time let’s see How to fix the underlying cause of this issue using the below-listed troubleshooting guide.
Fix Unable to turn on Windows Defender in Windows 10
确保创建一个还原点，以防出现问题。
Method 1 – Uninstall any third-party Antivirus software
One of the most common causes of Windows Defender not working is third-party antivirus software. Windows Defender automatically shuts itself down once it detects any third party anti-malware software installed on your system. Therefore, you need to first start uninstallation any third party antimalware software. Moreover, you need to make sure that uninstallation is done properly all residue files of that software otherwise it will keep creating a problem for Windows Defender to get started. You can use some uninstaller software that will remove all remnants of your previous antivirus. Once the installations finished, you need to restart your system.
Method 2 – Run System File Checker (SFC)
Another method that you can opt for is system file diagnosis and repair. You can use command prompt tool to check whether Windows Defender files are corrupted. Moreover, this tool repairs all corrupted files.
1.按 Windows 键 + X，然后选择 命令提示符（管理员）.
2.类型 SFC / SCANNOW 并回车。
3.This process takes some time so be patient while running this command.
4.In case sfc command did not resolve the problems, you can use another command. Just type the below-mentioned command and hit Enter:
DISM / Online / Cleanup-Image / RestoreHealth
5.It will scan thoroughly and repair corrupted files.
6.After completing these steps, check if you’re able to fix Can’t Turn ON Windows Defender issue or not.
方法 3 – 执行干净启动
Sometimes there are some third party applications cause this problem, you can easily find those ones by performing the clean boot function.
1.Press Windows + R and type MSCONFIG 并按Enter键。
2.On the system configuration Window, you need to navigate to 服务标签 where you need to check to 隐藏所有Microsoft服务 并点击 全部禁用 按钮。
3.导航到 Startup section 并点击 打开任务管理器。
4.Here you will locate all startup programs. You need to 右键单击 on each program and 关闭 all of them one by one.
5.After disabling all startup applications you need to come back to the system configuration window to 保存所有更改。 点击 确定。
6.You need to reboot your system and check if you’re able to Fix Can’t Turn ON Windows Defender issue 或没有。
To zero in on the issue you need to perform clean boot using this guide and find the problematic program.
Method 4 – Restart Security Center Service
Another method to get your Windows Defender problem solved is restarting security center service. You need to activate and ensure that certain services are enabled.
1.Press Windows + R and type SERVICES.MSC 然后按Enter
2.Here you need to search for 安全中心 然后 右键单击 on Security Center and choose 重新启动 选项。
3.Now simply restart your device and check if the problem is solved or not.
Method 5 – Modify your registry
If you are still finding the problem in turning on the Windows Defender, you can opt for this method. You just need to modify the registry but before doing so make sure to create a backup of your Registry.
1.Press Windows + R and type 注册表编辑器. 现在按 Enter。
2.Once you open the registry editor here you need to navigate to:
HKEY_LOCAL_MACHINESOFTWAREP策略MicrosoftWindows Defender
3.Select Windows Defender then in the right window pane find DisableAntiSpyware DWORD. Now double click this file.
4.Set the value data to 0 and click OK to save the settings.
请注意： If you’re facing permission issues then right-click on Windows Defender的 并选择 权限。 Follow this guide in order to take full control or ownership of the above registry key and again set the value to 0.
5.Most probably, after doing this step, your Windows Defender will start working on your system properly without any problem.
方法6 – Set Windows Defender Service to Automatic
请注意： 如果 Windows Defender 服务在服务管理器中显示为灰色，则 跟随这篇文章.
1.按Windows键+R然后输入 SERVICES.MSC 并按Enter键。
2.在“服务”窗口中找到以下服务：
Windows Defender 防病毒网络检查服务
Windows Defender 防病毒服务
Windows Defender 安全中心服务
3.双击它们中的每一个并确保它们的启动类型设置为 自动表 如果服务尚未运行，请单击“启动”。
4.单击“应用”，然后单击“确定”。
5.重新启动您的电脑以保存更改并查看是否能够 Fix Can’t Turn ON Windows Defender issue.
方法7 – 设置正确的日期和时间
1.Click 日期和时间 任务栏上，然后选择“日期和时间设置设立的区域办事处外，我们在美国也开设了办事处，以便我们为当地客户提供更多的支持。“
2.如果在 Windows 10 上，则使“自动设定时间“要”on设立的区域办事处外，我们在美国也开设了办事处，以便我们为当地客户提供更多的支持。“
3.对于其他人，点击“互联网时间”并勾选“自动与互联网时间服务器同步设立的区域办事处外，我们在美国也开设了办事处，以便我们为当地客户提供更多的支持。“
4.选择服务器“时间.windows.com”，然后单击更新和“确定”。您不需要完成更新。只需单击“确定”即可。
Again check if you are able to Fix Windows Defender Does Not Start issue or not, if not then continue with the next method.
Method 8 – Run CCleaner and Malwarebytes
2.运行恶意软件字节 并让它扫描您的系统是否有有害文件。
3.如果发现恶意软件，它将自动删除它们。
4.现在运行 CCleaner的 在“Windows”选项卡下的“清理”部分中，我们建议检查以下要清理的选项：
5.一旦您确定检查了正确的点，只需单击 运行清洁工， 让 CCleaner 顺其自然。
6.要清理系统，请进一步选择“注册表”选项卡并确保选中以下内容：
7.选择扫描问题并允许CCleaner扫描，然后单击 修复选定的问题。
8.当CCleaner询问“您想要备份对注册表的更改吗？”选择是。
9.备份完成后，选择“修复所有选定的问题”。
10.重新启动您的电脑以保存更改并查看是否能够 Fix Can’t Turn ON Windows Defender issue.
Method 9 – Update Windows Defender
1.按 Windows 键 + X，然后选择 命令提示符（管理员）。
2.在 cmd 中键入以下命令，并在每一条命令后按 Enter 键：
“%PROGRAMFILES%Windows DefenderMPCMDRUN.exe” -RemoveDefinitions -All
“%PROGRAMFILES%Windows DefenderMPCMDRUN.exe” -SignatureUpdate
3.Once the command finish processing, close cmd and reboot your PC.
Method 10 – Update Windows 10
1.按 Windows 键 + I 打开“设置”，然后单击“更新与安全“图标。
2.现在，请确保从左侧窗格中选择 Windows更新。
3.接下来，单击“检查更新”按钮，让 Windows 下载并安装任何挂起的更新。
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Hopefully, above mentioned all methods will help you to Fix Unable to turn on Windows Defender in Windows 10 Issue. However, you need to understand that these methods should be followed systematically. In case you have more questions related to this problem leave your comments below.
