我们的一位读者报告说，所有文件扩展名都已更改为某种未知文件格式。如果是这样，那可能是病毒！如果病毒已将所有文件扩展名更改为未知应用程序，则将默认文件扩展名、格式和图标恢复为原始状态。

我的 PC 上的所有文件扩展名都已更改；是病毒吗？

您可能不小心将文件的默认选项设置为其他内容。但是，如果所有人都发生这种情况，最好先用防病毒软件^(antivirus)扫描您的 PC，然后再执行其他任何操作。它可以是启动计时器的 Windows Defender^{(Windows Defender at Boot timer)}或您在安全模式下使用的任何人，^{(in Safe Mode,)}以获得最佳效果。您也可以使用第二意见的便携式扫描仪^{(second-opinion portable scanner)}来加倍确定。

如果扫描清晰，或者您能够删除导致问题的所有受感染文件，那么是时候重置默认关联，以便它可以在其指定的应用程序中打开。一个接一个地尝试这些方法。您可能需要管理员权限才能解决它。

1. 在 Windows 设置中重置默认值
2. 删除用户选择文件夹
3. 通过文件关联修复程序重置
4. 使用勒索软件解密工具。

1]在Windows设置中^{(Windows Settings)}重置默认值^{(Reset Defaults)}

在Windows 10中，打开设置^(Settings)( Win + I)，然后转到Apps > Default应用程序。向下滚动^(Scroll)直到您看到 重置为 Microsoft 推荐^{(Reset to Microsoft recommended defaults)(Reset to Microsoft recommended defaults)}的默认值，然后单击重置按钮。^{(Reset button.)}

在Windows 11中，打开设置^(Settings)( Win + I)，然后转到Apps > Default应用程序。向下滚动^(Scroll)直到您看到重置所有默认应用程序^{(Reset all default apps)}，然后单击重置按钮。^{(Reset button.)}

您也可以通过转到经典的Control Panel > Default Programs来实现此目的。但是，它会将您带到同一个地方。

2]删除用户选择文件夹

如果这没有帮助，请先创建一个系统还原点，然后尝试以下操作：

打开 Regedit   （使用^{(  ()}Win + R打开运行^(Run)提示，然后键入regedit ，然后按Enter键）

然后导航到以下键：

HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionExplorerFileExts

展开 FileExts。在这里，您将看到文件扩展名文件夹的列表。

您必须一个接一个地展开它们，如果您在它下面看到一个UserChoice 文件夹，请删除UserChoice文件夹。

3]通过文件关联修复程序重置

您可以下载或免费软件File Association Fixer v2并手动恢复每个文件关联。就像我们在上面看到的，损坏的文件关联通常是由于注册表损坏造成的。该软件可以帮助您修复它。

4]使用勒索软件解密工具

如果您看到不寻常的文件扩展名，则可能是某些勒索软件锁定了您的文件。看看这些勒索软件解密工具^{(ransomware decryption tools)}是否对您有帮助 - 希望有一个可用于您的勒索软件！这篇文章更多地讨论了 勒索软件攻击和其他常见问题解答^{(Ransomware Attacks & other FAQ)}。

我希望这篇文章很容易理解，并且您可以解决文件^(File)关联的问题。如果病毒不是问题，则一定是软件安装或手动干预导致它，您可能需要使用重置此 PC^{(Reset This PC)}选项。

Virus has changed all file extensions on my Windows 11/10 PC

One of our readerѕ reported that all the file extensions have changed to some unknown file format. If so, it could be a virus! If a virus has changed all thе files extensions to unknown applications, then restore default file extensions, format & icons to the original state thus.

All file extensions changed on my PC; Is it a virus?

It is possible that you may have accidentally set the default option of files to something else. However, if this is happening for all, it is better that you scan your PC with an antivirus first before doing anything else. It can be Windows Defender at Boot timer or anyone which you use in Safe Mode, for the best results. you may also use a second-opinion portable scanner to be doubly sure.

If the scan is clear, or you were able to remove all the infected files which caused the problem, then it’s time to reset the default association so it can open in its specified application. Try these methods one after the other. You may need admin permission to resolve it.

1. Reset Defaults in Windows Settings
2. Delete UserChoice folder
3. Reset via File Association Fixer
4. Use Ransomware Decryption Tool.

1] Reset Defaults in Windows Settings

In Windows 10, open Settings (Win + I), and then go to Apps > Default apps. Scroll down till you see Reset to Microsoft recommended defaults and click on the Reset button.

In Windows 11, open Settings (Win + I), and then go to Apps > Default apps. Scroll down till you see Reset all default apps and click on the Reset button.

You can also achieve this by going to the classic Control Panel > Default Programs. However, it will bring you to the same place.

2] Delete UserChoice folder

If this does not help, create a system restore point first and then try this:

Open Regedit  (Open Run prompt using Win + R, and then type regedit followed by pressing the Enter key)

Then navigate to the following key:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts

Expand FileExts. Here you will see a list of file extension folders.

You will have to expand each of them, one after the other, and if you see a UserChoice folder under it, delete the UserChoice folder.

3] Reset via File Association Fixer

You can download or freeware File Association Fixer v2 and restore each file association manually. Like we saw above, the broken file associations are typically caused due to a corrupted Registry. This software can help you fix it.

4] Use Ransomware Decryption Tool

If you see an unusual file extension, maybe some ransomware has locked your files. See if any of these ransomware decryption tools help you – Hope one is available for your ransomware! This post talks a little more about Ransomware Attacks & other FAQ.

I hope the post was easy to follow, and you could resolve the problem with File associations. If the virus was not a problem, then either a software installation or manual intervention must have caused it and you may be required to use Reset This PC option.

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