Windows Defender或Microsoft Defender或Windows 安全通过^{(Windows Security)}Windows 更新^{(Windows Updates)}获取其定期更新。但是，如果由于某种原因，定义更新无法按预期进行，那么您可以尝试几种方法来解决它。当您收到没有最新定义或无法检查、下载或安装更新的消息时，请按照这些操作。

Windows Defender未在Windows 11/10

如果Windows 11/10 中的Microsoft Defender ( Windows Security ) 未自动更新，您可以按照以下建议解决定义更新问题：

• 手动检查Windows Defender中的更新^{(Windows Defender)}
• 运行 Windows 更新疑难解答
• ^{(Trigger Microsoft Defender)}使用命令行触发 Microsoft Defender更新

您将需要其中一些管理员权限，因此请确保您的帐户具有足够的权限。

1 ] 手动^{(] Manually)}检查Windows Defender中的更新^{(Windows Defender)}

有时这是一个临时问题，您需要做的就是重新启动 PC。完成后，请按照以下步骤操作：

1. 打开 Windows 安全
2. 点击^(Click)病毒^(Virus)和威胁防护
3. 然后单击检查^(Check)更新，然后再次单击检查^(Check)更新
4. 它将开始寻找新的定义更新。

阅读^(Read)：如何手动更新 Windows Defender^{(How to update Windows Defender manually)}。

2]运行Windows更新疑难解答^{(Run Windows Update Troubleshooter)}

Virtus定义更新通过Windows 更新^{(Windows Updates)}推出。如果更新服务有问题，那么就会导致问题。值得庆幸的是，Windows^{(Thankfully Windows)}带有内置的Windows 更新疑难解答程序，可以解决大部分需要大量手动操作的问题。

1. 打开 Windows 10 设置（Win + I）
2. 导航^(Navigate)到更新^(Update)和Security > Troubleshoot
3. 单击^(Click)Windows 更新^{(Windows Update)}，然后单击运行疑难解答^(Run)按钮。

向导完成该过程后，使用Windows Update^{(Windows Update)}检查定义更新。

3]使用命令行触发 Microsoft Defender更新^{(Trigger Microsoft Defender)}

您可以手动触发对设备的更新。该命令将清除当前缓存并触发更新。您可以直接在提升的命令提示符下运行它，或者创建一个以管理员身份运行以下命令的批处理脚本：

cd %ProgramFiles%Windows Defender

MpCmdRun.exe -removedefinitions -dynamicsignatures

MpCmdRun.exe -SignatureUpdate

阅读^(Read)：如何使用 Windows PowerShell 更新 Windows Defender 定义^{(How to update Windows Defender definitions using Windows PowerShell)}。

最后一部分也适用于企业^(Enterprise)计算机，可供管理员或 IT 管理员使用。

我希望这篇文章能帮助您弄清楚如何解决Microsoft 安全^{(Microsoft Security)}或 Windows Defender更新。

如果这些都不起作用，您可以随时连接到Microsoft 支持^{(Microsoft Support)}团队，并寻求他们的帮助来解决问题。

可能对您有所帮助的类似帖子^{(Similar post that may help you)}：

• 错误 8024402f， Windows 11 上的保护定义更新失败
• Windows Defender 不会更新错误代码为 0x8024402c、0x80240022、0X80004002、0x80070422、0x80072efd、0x80070005、0x80072f78、0x80072ee2、0x8007001B 的定义。

Windows Defender not updating automatically in Windows 11/10

Windows Defender or Miсrosoft Defender or Windows Security gets its regular updateѕ through Windows Updates. However if for some reason, the definitіon updatе is not able to proceed as expected, then you can try a coυple of methоds to resolve it. Follow these when you either receive the message that you don’t have the latest definition or updates that cannot be checked, downloaded, or installed.

Windows Defender not updating automatically in Windows 11/10

If Microsoft Defender (Windows Security) in Windows 11/10 does not update automatically, you can ou can troubleshoot definition update issues, by following these suggestions:

• Manually check for updates in Windows Defender
• Run Windows Update Troubleshooter
• Trigger Microsoft Defender updates using the command line

You will need admin privileges for some of them so make sure your account has sufficient privileges.

1] Manually check for updates in Windows Defender

Sometimes it is a temporary issue, and all you need to do is restart your PC. Once you do that follow the steps as below:

1. Open Windows Security
2. Click on Virus and threat protection
3. Then click on Check for updates and then again click on Check for update
4. It will start looking for new definition updates.

Read: How to update Windows Defender manually.

2] Run Windows Update Troubleshooter

Virtus definition updates are rolled out through Windows Updates. If the update service has issues, then it will cause the problem. Thankfully Windows comes with built-in Windows Update Troubleshooter that can resolve most of the issues which takes a lot of manual effort.

1. Open Windows 10 Settings ( Win + I)
2. Navigate to Update and Security > Troubleshoot
3. Click on Windows Update, and then click on Run the troubleshooter button.

Once the wizard completes the process, check for the definition update using Windows Update.

3] Trigger Microsoft Defender updates using command line

You can manually trigger the update to devices. The command will clear the current cache and trigger an update. You can directly run this on an elevated command prompt or create a batch script that runs the following commands as an administrator:

cd %ProgramFiles%\Windows Defender

MpCmdRun.exe -removedefinitions -dynamicsignatures

MpCmdRun.exe -SignatureUpdate

Read: How to update Windows Defender definitions using Windows PowerShell.

The last section is also applicable for the Enterprise computers and can be used by administrators or IT admins.

I hope the post helped you to figure out how you can resolve the Microsoft Security or Windows Defender update.

In case none of these works, you can always connect to the Microsoft Support team, and take their help to resolve the problem.

Similar post that may help you:

• Error 8024402f, Protection definition update failed on Windows 11
• Windows Defender will not update definitions with error codes 0x8024402c, 0x80240022, 0X80004002, 0x80070422, 0x80072efd, 0x80070005, 0x80072f78, 0x80072ee2, 0x8007001B.

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