Windows Update is used to keep Microsoft Windows and other Microsoft programs updated. Being one of the most essential services for the operating system, it downloads and installs the security updates regularly to Windows. However, they can cause errors at times that becomes a highly disturbing moment at that situation. One such error 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:
- Run Windows Update Troubleshooter
- 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.
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.