Windows Update用于保持Microsoft Windows和其他Microsoft程序的更新。作为操作系统最重要的服务之一，它会定期将安全更新下载并安装到Windows。但是，它们有时会导致错误，在这种情况下会变得非常令人不安。一个这样的错误是Windows Update Error C8000266。

C8000266: Windows Update encountered an unknown error

在本指南中，我们解释了一些可能会帮助您摆脱此问题的快速修复。那么，让我们开始吧。

Windows 更新错误 C8000266

要修复Windows 更新错误 C8000266^{(Windows Update Error C8000266)}，请遵循以下建议：

1. 运行 Windows 更新疑难解答
2. 重置Windows更新组件

让我们详细了解它们：

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

Windows 更新疑难解答是一个很棒的内置工具，它肯定可以修复计算机上大多数常见的更新相关问题。运行此应用程序的过程如下：

要开始使用，请先打开 Windows 设置^{(open the Windows Settings)} (Win+I)。

然后选择更新和安全^{(Update & Security)}>Troubleshoot > Additional troubleshooters.

在下一页上，选择Windows 更新^{(Windows Update)(Windows Update)}，然后单击运行疑难解答 ^{(Run the troubleshooter )}按钮。

等待^(Wait)一段时间，直到它检测并解决整个问题。

完成该过程后，关闭疑难解答程序，然后重新启动设备。

此外，您还可以尝试运行Windows 更新在线疑难解答^{(Windows Update Online Troubleshooter)}。

现在转到Windows 更新^{(Windows Update)}并尝试安装挂起的更新。

如果您仍然面临问题，请移至下一个潜在的解决方案。

2]重置^(Reset)Windows更新^(Windows)组件

如果运行Windows 更新疑难解答^{(Windows Update Troubleshooter)}无法解决问题，您可以手动重置Windows 更新组件。^{(Windows Updates Components)}这是您可以用来执行此操作的快速指南：

Win+R键盘快捷键打开运行对话框。

键入 cmd 并按Ctrl+Shift+Enter打开提升的命令提示符。

如果屏幕上出现UAC提示，请单击“是”授予他们权限。

在提升的命令提示符窗口中，键入以下命令并在每一行上按 Enter。

net stop bits
net stop wuauserv
net stop appidsvc
net stop cryptsvc

这将停止运行后台智能传输服务^{(Background Intelligent Transfer Service)}或BITS、Windows 更新^{(Windows Update)}服务和加密^{(Cryptographic)}服务。

现在您需要通过从设备中删除所有qmgr*.dat 文件来重置Windows 更新组件。^{(Windows Update)}

为此，请在命令提示符下键入以下命令行，然后按 Enter 键执行它。

Del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat"

要确认删除，请从键盘上键入Y。

接下来，重命名SoftwareDistribution 和 catroot2文件夹。

为此，请在命令提示符窗口中键入以下命令。此外，请确保在键入每个命令后按 Enter。

Ren %systemroot%\SoftwareDistribution SoftwareDistribution.bak
Ren %systemroot%\system32\catroot2 catroot2.bak

接下来，您必须将BITS服务和Windows Update服务重置为其默认安全描述符

为此，请在提升的命令提示符窗口中键入以下命令：

sc.exe sdset bits D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)
sc.exe sdset wuauserv D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)

按^(Press)回车键执行命令并在每个命令后按回车键。

在命令提示符窗口中键入以下文本代码以移动到System32目录。然后按Enter。

cd /d %windir%\system32

现在输入以下命令，并确保在您输入的每个命令后按回车键。

regsvr32.exe atl.dll
regsvr32.exe urlmon.dll
regsvr32.exe mshtml.dll
regsvr32.exe shdocvw.dll
regsvr32.exe browseui.dll
regsvr32.exe jscript.dll
regsvr32.exe vbscript.dll
regsvr32.exe scrrun.dll
regsvr32.exe msxml.dll
regsvr32.exe msxml3.dll
regsvr32.exe msxml6.dll
regsvr32.exe actxprxy.dll
regsvr32.exe softpub.dll
regsvr32.exe wintrust.dll
regsvr32.exe dssenh.dll
regsvr32.exe rsaenh.dll
regsvr32.exe gpkcsp.dll
regsvr32.exe sccbase.dll
regsvr32.exe slbcsp.dll
regsvr32.exe cryptdlg.dll
regsvr32.exe oleaut32.dll
regsvr32.exe ole32.dll
regsvr32.exe shell32.dll
regsvr32.exe initpki.dll
regsvr32.exe wuapi.dll
regsvr32.exe wuaueng.dll
regsvr32.exe wuaueng1.dll
regsvr32.exe wucltui.dll
regsvr32.exe wups.dll
regsvr32.exe wups2.dll
regsvr32.exe wuweb.dll
regsvr32.exe qmgr.dll
regsvr32.exe qmgrprxy.dll
regsvr32.exe wucltux.dll
regsvr32.exe muweb.dll
regsvr32.exe wuwebv.dll

这将重新注册所有相应的BITS文件和Windows 更新^{(Windows Update)}相关的DLL文件

现在您需要重置可能导致问题错误的网络配置。

为此，请输入以下命令行并在每个命令行后按回车键。

netsh winsock reset
netsh winsock reset proxy

全部完成后，您需要重新启动之前停止的服务，例如后台智能传输服务^{(Background Intelligent Transfer Service)}或BITS、Windows 更新^{(Windows Update)}和加密^{(Cryptographic)}服务。

为此，请再次转到命令提示符并输入以下命令行。另外，不要忘记在每个命令后按回车键。

net start bits
net start wuauserv
net start appidsvc
net start cryptsvc

最后，在命令提示符^{(Command Prompt)}中键入 Exit以关闭窗口。

完成整个过程后，重新启动Windows PC 以应用更改。

启动后，转到Windows 更新^{(Windows Updates)}并尝试安装计算机上可用的挂起更新。

我们希望上述方法可以帮助您解决此问题。 ^{(We hope the above-mentioned method would help you to resolve this issue. )}

Fix Windows Update Error C8000266?

Windows Update is used to keep Mіcrosoft Windows and other Mіcrosoft programs updated. Being one of the most essential services fоr the operating system, it downloads and installѕ the securitу updates regularly to Windows. However, they can cause errors at times that becomes a highly dіsturbing momеnt at that ѕituation. One such еrror is Windows Update Error C8000266.

C8000266: Windows Update encountered an unknown error

In this guide, we have explained some quick fixes that will possibly help you to get rid of this problem. So, let’s get started.

Windows Update Error C8000266

To fix Windows Update Error C8000266, follow the below suggestion:

1. Run Windows Update Troubleshooter
2. Reset the Windows Updates Components

Let us see them in details:

1] Run Windows Update Troubleshooter

The Windows Update troubleshooter is a great built-in tool that can certainly fix most of the common update related issues on the computer. The procedure to run this application is as follows:

To get it started, open the Windows Settings (Win+I) first.

Then select Update & Security > Troubleshoot > Additional troubleshooters.

On the next page, select Windows Update and then click Run the troubleshooter button.

Wait for a while until it detects and solves the problem throughout.

Once it completes the process, close the troubleshooter, and restart your device.

Furthermore, you can also try running the Windows Update Online Troubleshooter.

Now go to the Windows Update and try to install the pending update.

If you’re still facing the problem move down to the next potential solution.

2] Reset the Windows Updates Components

If running Windows Update Troubleshooter doesn’t fix the problem, you can reset the Windows Updates Components manually. Here is a quick guide you can use to do so:

Open Run dialog box using Win+R keyboard shortcut.

Type in cmd and press Ctrl+Shift+Enter to open an elevated command prompt.

If UAC prompts on the screen, click Yes to grant them permission.

On the elevated command prompt window, type in the following commands and hit enter on each line.

net stop bits
net stop wuauserv
net stop appidsvc
net stop cryptsvc

This will stop running the Background Intelligent Transfer Service or BITS, Windows Update service, and Cryptographic service.

Now you need to reset Windows Update components by removing all the qmgr*.dat files from your device.

To do so, type the below command-line in the command prompt and hit enter to execute it.

Del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat"

To confirm the deletion, type Y from your keyboard.

Next, rename the SoftwareDistribution and catroot2 folders.

To do that, type the following commands in the command prompt window. Also, make sure to hit enter after you type each command.

Ren %systemroot%\SoftwareDistribution SoftwareDistribution.bak
Ren %systemroot%\system32\catroot2 catroot2.bak

Next, you have to reset the BITS service and the Windows Update service to its default security descriptor

To do this, type the below commands in the elevated command prompt window:

sc.exe sdset bits D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)
sc.exe sdset wuauserv D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)

Press enter to execute the command and hit enter after each one.

Type the below text code in the command prompt window to move to the System32 directory. Then press Enter.

cd /d %windir%\system32

Now input the following commands and make sure to hit enter after each command you type there.

regsvr32.exe atl.dll
regsvr32.exe urlmon.dll
regsvr32.exe mshtml.dll
regsvr32.exe shdocvw.dll
regsvr32.exe browseui.dll
regsvr32.exe jscript.dll
regsvr32.exe vbscript.dll
regsvr32.exe scrrun.dll
regsvr32.exe msxml.dll
regsvr32.exe msxml3.dll
regsvr32.exe msxml6.dll
regsvr32.exe actxprxy.dll
regsvr32.exe softpub.dll
regsvr32.exe wintrust.dll
regsvr32.exe dssenh.dll
regsvr32.exe rsaenh.dll
regsvr32.exe gpkcsp.dll
regsvr32.exe sccbase.dll
regsvr32.exe slbcsp.dll
regsvr32.exe cryptdlg.dll
regsvr32.exe oleaut32.dll
regsvr32.exe ole32.dll
regsvr32.exe shell32.dll
regsvr32.exe initpki.dll
regsvr32.exe wuapi.dll
regsvr32.exe wuaueng.dll
regsvr32.exe wuaueng1.dll
regsvr32.exe wucltui.dll
regsvr32.exe wups.dll
regsvr32.exe wups2.dll
regsvr32.exe wuweb.dll
regsvr32.exe qmgr.dll
regsvr32.exe qmgrprxy.dll
regsvr32.exe wucltux.dll
regsvr32.exe muweb.dll
regsvr32.exe wuwebv.dll

This will re-register all the respective BITS files and Windows Update related DLL files

Now you need to reset the network configurations that might be the role of the problematic error.

To do so, type in the below command-line and hit enter after each one.

netsh winsock reset
netsh winsock reset proxy

Once it is all completed, you need to restart the services you stopped it earlier like Background Intelligent Transfer Service or BITS, Windows Update, and Cryptographic services.

To do so, again go to the command prompt and type in the below command line. Also, don’t forget to press enter after each command.

net start bits
net start wuauserv
net start appidsvc
net start cryptsvc

Finally, type Exit in the Command Prompt to close the window.

Once you complete the entire process, restart your Windows PC to apply the changes.

After it starts up, go to the Windows Updates and try to install the pending updates available on the computer.

We hope the above-mentioned method would help you to resolve this issue. 

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