0x80070643 is an error that many users of Windows computers have reported. It is an error that appears on your screens while the automatic update of your Windows takes place. The code appears with the message “Definition Update for Windows Defender – Error 0x80070643” and causes the failure of the Windows Defender Update.

To Fix Windows Update Error Code 0x80070643: Use antivirus-specific removal tools, Check your system files and perform a Clean boot, Restart the Security Center Service, and Perform a final manual update. 

This error signifies that a fault has occurred during the installation process. Though the download of this update takes place properly, the error pops up and restricts the update from getting installed completely. Read the complete article to fix the error quickly.

How to Fix Windows Update Error Code 0X80070643

The error code 0x80070643 can appear due to the presence of some of the undeleted files of previous antivirus programs or if there are corrupted files in the registries of your system.

fix windows update error code 0X80070643

Many users are looking for potential methods to help them solve this issue by themselves. However, several ways or solutions can be used to fix the error code 0x80070643. Though, different users may face this error for various reasons. So, one method that works for a particular user might not work for another. So check out all the possible solutions to your problem below and then choose which one suits your purpose and apply it to eliminate it.

Method #1 Restart Your Computer

Sometimes more significant problems are solved by the most accessible solutions. Restarting your PC is one method you should use in any case that displays your error, whether it is error code 0x80070643 or any other issue.

restart pc

So, restart your computer and install the program again, as sometimes the previous installation requires restarting your computer system. For any issue related to Windows restart, refer to this helpful guide.

Method #2 Disable Antivirus Program

The error code 0x80070643 can be caused due to some conflicts between the Antivirus software of your PC and the other applications or Windows updates present on your computer. In such a case, you can temporarily turn off your Antivirus software to check if it can solve the issue. Afterward, go to Windows Update and check if you can update your system. Follow the steps to disable the Antivirus:

  1. First, Right-click on the icon of your Antivirus software from the system tray and click Disable.Disable Antivirus Protection
  2. Then select the time frame you want to turn off your Antivirus program. (It is recommended to choose the minimum time frame available there, which could be 15 or 30 minutes)
  3. Now run Windows Defender and check if the message Windows Defender Update fails with the error code 0x80070643 is gone or not.

Related: – Fix: Feature Update To Windows 10 Version 1903 – Error 0x80080008

Method #3 Install the Latest Version of the .NET Framework

.NET Framework plays an essential role in the installation of system updates. If you don’t have .NET Framework on your PC or its version has become outdated, you won’t be able to install the system updates. So download and install the latest version of .NET Framework from Microsoft on your PC. Follow the steps to download .NET Framework:

  1. First, Navigate to Microsoft .NET Framework’s official website.Microsoft .Net Framework
  2. Then select the latest available version of the .NET Framework..Net Framework Latest Version
  3. Afterward, you can download other old versions of the .NET Framework if required.Other .NET Framework Downloads
  4. Then click on the Download button & it will take a few seconds to initiate the process.Download in Progress

Now open the downloaded file on your PC or laptop and follow the on-screen instructions to install it.

After installing this application, rerun Windows Update to check if you can install the system updates now.

Method #4 Restart Windows Installer Service on Your PC

There could be some faulty configurations in your system’s Windows Installer Service, which may lead to the error code 0x80070643 appearing on your screens. Restarting the Windows Installer Service might fix the error code on your PC. Follow the steps to do this:

  1. First, press the Win + R keys simultaneously on your keyboard. Now type “services. msc” and hit Enter key to open the Services window on your PC.Type Services.msc
  2. Next, click on the Windows Installer option and then on Restart.Restart Windows Installer Service

Afterward, check if your problem of error code 0x80070643 has been resolved or not.

Method #5 Manually Update Windows Defender on Your PC

  1. First, press the Windows + Q keys simultaneously and search for Windows Defender.windows defender settings
  2. Now, click on Virus & Threat Protection option under Protection Areas.Virus & Threat Protection Settings
  3. Then click on Virus & threat protection updates button.Virus & threat protection updates
  4. Now, just hit the check for updates button. It will take a few minutes to download the latest updates, ensuring your system is protected against various threats, including potential issues like “dev error 6068”.Check for Updates

Finally, reboot your computer now and save the changes.

Alternatively, you can use Command Prompt to update Windows Defender in your system by following the steps:

  1. First, Press Windows + X keys simultaneously and choose Command Prompt (Admin).Command Prompt (Admin)
  2. Afterward, type the command given below in cmd and press Enter key after typing each one of them:
    “%PROGRAMFILES%\Windows Defender\MpCmdRun.exe” – Remove Definitions -All
    “%PROGRAMFILES%\Windows Defender\MpCmdRun.exe” – SignatureUpdateMpCmdRun.exe

After the commands are entered, the processing will take place. Finally, close cmd and reboot your system now.

Method #6 Run Scannow or SFC on Your PC

If any corrupted files are present in your computer system, they can stop your computer’s Windows from getting updated. Using an SFC scan, you can find out the corrupted files in your system and replace them with the right ones. Follow the steps to run scannow or sfc:

  1. First, press Windows Key + X together & choose Command Prompt (Admin) from the menu.Command Prompt (Admin)
  2. Then type “sfc / scannow” in the Command Prompt and hit Enter key.SFC Scannow

Afterward, wait a few minutes to let your PC complete the scanning. Now try to install System Updates. If it works now, your problem with the 0x80070643 error code has been resolved.

Method #7 Perform a Clean Boot of Your PC

The presence of third-party software and programs can conflict with Windows in your system, which may result in the error code 0x80070643. In such a case, you must perform a clean boot of your system and check if it solves the issue.

Method #8 Use Troubleshooting

  1. First, click on the Start menu, type “troubleshoot” in the search box, and click on the Troubleshoot option displayed.troubleshoot
  2. Now, extend the Windows Update option & click on the Run the troubleshooter button.Run the troubleshooter
  3. Afterward, follow the on-screen instructions and run the Windows Update Troubleshoot. Restart your computer and check if you can fix the error code 0x80070643.

Method #9 Use the System Restore feature

It allows you to restore your Windows Operating System when it is stable and working correctly. This step doesn’t cost you the loss of your data or personal information.system restore

So if you are facing the error code 0x80070643 on your computer screens during the installation of Windows Update, create a system restore point and then use your computer without any error.

Method #10 Reset the Components of Windows Updates to Fix the Issue

1. At First, Press Windows + X keys and click on Command Prompt (Admin).


2. Then type the commands mentioned below and hit Enter key after each one to stop Windows Update Services:

net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver

Net Stop Commands

3. Afterwards, type the commands given below to rename the Software Distribution Folder and press Enter key after each one:

Ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
Ren C:\Windows\System32\Catroot2 catroot2.old

4. Then type the given commands to start the Windows Update Services and press Enter key after typing each command:

net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Net Stop Commands

At last, reboot your system to save the changes made and check whether the error code 0x80070643 has disappeared.

Method #11 Uninstall Windows Defender Update

People using Windows 10 Operating System know there is no System Restore point on Windows 10. Also, it is frustrating to do random reboots every day. However, if you are also stuck in this situation and are facing the error code 0x80070643, then you can remove Windows Defender Update and get back to the early state of Windows by following the steps below:

  1. First, Press Windows + R keys simultaneously to open the Run window. Then type “appwiz. cpl” and hit Enter to open Programs and Features.Type appwiz
  2. Afterward, click the View Installed Updates icon on your screen’s left side.View installed updates
  3. Now scroll down to Microsoft Windows and right-click on the Windows Defender or KB4054517 Update, which is the cause of the error code 0x80070643.Uninstall KB4054517 Finally, click Uninstall and restart your PC to check if your issue persists.

Method #12 Update Using Administrative Permissions

Sometimes, users need to configure the administrative permissions as some updates require administrative permissions to be install. If you haven’t signed up on your PC and are using it as a guest or a lesser privileged account, sign in to your system first. update using administrative permissionsIf your computer belongs to a specific domain you are unaware of, call your system administrator to help you.

Method #13 Run SubInACL Tool

Users of old Windows Operating Systems like Windows Vista or Windows XP must know that there is a bug that involves .NET Framework 2.0, which occurs due to incorrect access control list permissions on registry hives that leads to causing hindrance for some applications from getting installed. MSI-based setups. Follow the steps to try this solution:

  1. First, Download the SubInACL tool & install it on your system. This tool will install into C:\ProgramFiles\Windows Resource Kits\Tools. Afterward, navigate to this file & copy-paste the code into your Notepad file. Then move to Navigate to File>>Save As.Save As
  2. Later, name it reset. Cmd. At last, change the file type to All Files.Reset.cmd

Now, right-click on the script and then on Run as Administrator. Wait to let the reset.cmd script be complete, and then try installing the software.


How can I fix Windows Update Error Code 0x80070643?

You can fix Windows Update Error Code 0x80070643 by running the Windows Update Troubleshooter, repairing the .NET Framework, or uninstalling and reinstalling the Windows Installer.

How do I run the Windows Update Troubleshooter?

Go to Settings > Update & Security > Troubleshoot > Windows Update > Run the troubleshooter to run the Windows Update Troubleshooter.

How do I repair the .NET Framework?

To repair the .NET Framework, go to Control Panel > Programs > Programs and Features > Microsoft .NET Framework > Change > Repair.

How do I uninstall and reinstall the Windows Installer?

To uninstall the Windows Installer, open Command Prompt as an administrator and type 'msiexec /unregister.' To reinstall the Windows Installer, type 'msiexec /regserver'.

How do I disable my antivirus temporarily?

To disable your antivirus temporarily, go to your antivirus program's settings and disable the antivirus temporarily.

What should I do if I need help with the solutions?

If none of the solutions work, you can try performing a clean boot, running a System File Checker scan, or seeking help from a technical support professional.


Many Windows Defender users have tried the abovementioned methods, and the success rate of using these solutions is quite good. So by performing any of these methods, the users can get rid of the error code 0x80070643 and resume their work uninterruptedly.


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