Windows Update Error 0x80070643

How To Fix Windows Update Installation Error 0x80070643 

Windows Update is a Microsoft service that provides updates for the Windows operating systems in forms of patches and service packs. Windows Update provides updates not only for the Windows operating system and other Microsoft software, but also for various popular hardware drivers. These updates usually include various Windows features enhancements and security updates like definition updates for Windows Defender. If you are reading this, then most probably you encountered the Windows Update installation error "0x80070643", that occurs when there are some problems installing Definition Update for Windows Defender. This error means that there was a fatal error during downloaded update installation.

Definition Update for Windows Defender helps you to ensure that this antimalware solution detects the latest threats and tweaks threats detection logic, it enhances the ability to accurately identify various threats. Not being able to install these definition updates can be a big problem. In other words, your computer can be at higher risk of being infected by malware or viruses. Good news is that this problem can be fixed using several methods like running the System File Checker, installing updates manually, renaming the SoftwareDistribution folder, running Windows Update troubleshooter or performing a clean boot. You will find all of these methods thoroughly described in our guide below. Simply apply those steps by following the described steps and hopefully you will be able to fix the Windows Update error "0x80070643" by completing one of the solutions.

Windows Update Error 0x80070643

Table of Contents:

Run Windows Update Troubleshooter

The first thing we recommend you to try is to use one of the Windows troubleshooters which could solve this problem without the need to use more complex solutions. Windows includes a number of troubleshooters designed to quickly diagnose and automatically resolve various computer problems. Troubleshooters cannot fix all problems, but they are a good place to start if you encounter a problem with your computer, operating system or connected devices. To start troubleshooting, go to Settings and type "troubleshoot", select "Troubleshoot" from the list.

run windows update troubleshooter step 1

Now find the Windows Update troubleshooter under "Troubleshoot" and select it. Click "Run the troubleshooter" button and Windows will start resolving problems that prevent you from properly updating Windows operating system. See if this troubleshooter is able to solve the problem and fix the Windows Update error "0x80070643". If not, then proceed to the next method.

run windows update troubleshooter step 2

[Back to Table of Contents]

Rename SoftwareDistribution Folder

Software Distribution folder is a temporary folder in which Windows stores the update files until they are completely downloaded. Then, Windows starts the updating process. Renaming this folder might solve the problem and fix the Windows Update error "0x80070643". To rename this folder (and Catroot2 folder as well), you will need to use Command Prompt. You will need to stop particular services, rename these two folders and then start stopped services again. Open Command Prompt as administrator by typing "command prompt" in Search, right-clicking the Command Prompt result and selecting the "Run as administrator" option.

rename software distribution folder step 1

Now type the following commands (press Enter after each):

net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old ren C:\Windows\System32\catroot2 catroot2.old
net start wuauserv
net start cryptSvc
net start bits
net start msiserver

rename software distribution folder step 2

Exit Command Prompt and restart the computer. See if this solves the problem and Windows is now able to complete the updating process and the Windows Update error "0x80070643" is now fixed.

[Back to Table of Contents]

Update Windows Defender Through The Windows Defender App

Another possible way to update Windows Defender and avoid the Windows Update error "0x80070643" is to update Windows Defender through the Windows Defender App. To do so, type "windows defender" in Search and click the "Windows Defender Security Center" result.

update windows defender through the windows defender app step 1

Now click the shield icon on the left pane and then click "Protection updates".

update windows defender through the windows defender app step 2

In the Protection updates window click the "Check for updates" button and let Windows to check for Windows Defender updates and install them. Update Windows Defender and see if you are still getting the Windows Update error "0x80070643" when trying to update Windows.

update windows defender through the windows defender app step 3

[Back to Table of Contents]

Temporarily Disable Any Third-Party Antivirus

It is possible that installed third-party antivirus software is interfering with Windows Update and causes the Windows Update error "0x80070643". To make sure that the installed third-party antivirus software is not the culprit of this error we recommend you to try to temporarily disable it and check if the error still persists. If disabling (or uninstalling) your antivirus actually helps, then we recommend you to switch to another antivirus software or to reinstall the currently installed one. If you are not sure how to disable your antivirus, then read this guide. There you will find instructions on how to disable some of the most popular antivirus programs.

[Back to Table of Contents]

Run System File Checker

Another thing you might want to try in order to fix the Windows Update error "0x80070643" is to run the System File Checker. It is a utility in Windows that allows users to scan for corruptions in Windows system files and restore corrupted files. This guide describes how to run the System File Checker tool (SFC.exe) to scan your system files and to repair missing or corrupted system files. The "sfc scannow" option is one of the several specific switches available in the sfc command, the Command Prompt command used to run System File Checker. To run it you need to open elevated Command Prompt. You must run an elevated Command Prompt in order to be able to perform SFC scan. Open Command Prompt using administrative privileges once again and type the "sfc /scannow" command, press Enter on your keyboard to execute this command. System File Checker will start and it should take some time to complete the scan. It should take about 15 minutes. Wait for the scanning process to complete and restart your computer. See if the Windows Update error "0x80070643" still persists.

run system file checker step 1

If the SFC scan couldn't fix the problem or for some reason you couldn't run the SFC scan then try to run the DISM scan and then try to run the SFC scan again. DISM stands for Deployment Image Servicing and Management and it can be used to repair and prepare Windows images, including the Windows Recovery Environment, Windows Setup, and Windows PE. To run DISM scan you need to open Command Prompt as administrator again and to type in this command: "DISM /Online /Cleanup-Image /RestoreHealth". Press Enter on your keyboard to execute it.

run system file checker step 2

[Back to Table of Contents]

Perform A Clean Boot

When you start Windows using a normal startup operation, several applications and services start automatically, and then run in the background. These programs include basic system processes, antivirus software, system utility applications, and other software that has been previously installed. These applications and services can cause software conflicts, and cause the Windows Update error "0x80070643". A clean boot is performed to start Windows using a minimal set of drivers and startup programs. This helps eliminate software conflicts that occur when you install a program or an update, or when you run a program in Windows. To perform a clean boot, type "system configuration" in Search and click on the "System Configuration" result.

perform a clean boot step 5

In the System Configuration window, click on the "Services" tab and then mark the "Hide all Microsoft services" checkbox. Then, click on "Disable all".

perform a clean boot step 2

Click the "Startup" tab and click "Open Task Manager".

perform a clean boot step 3

Under the Task Manager's Startup tab, select the first application and click "Disable" to disable it. Disable all applications one by one, repeating this step. Once all programs are disabled, close Task Manager and click "OK" in the System Configuration's Startup tab. Restart the computer, run Windows Update (or update Windows Defender through Windows Defender app) again and see if this helps to fix the Windows Update error "0x80070643".

perform a clean boot step 4

[Back to Table of Contents]

Download And Install Updates Manually

In order to download and install updates manually you will need to download them from Microsoft Update Catalog. The Microsoft Update Catalog is a website that offers updates for computers running Windows operating systems. Created by Microsoft, the service provides a list of updates for corporations to distribute over a network. Security updates are released once a month on the website, except in special circumstances; for instance, in the event of a widespread computer virus or worm, Microsoft releases a corresponding update as soon as possible. Visit Microsoft Update Catalog and start your search by entering the update number that should be given next to the Windows Update error "0x80070643", for example "KB4048955". Click "Search" and look for the right version that suits your operating system. If you are not sure what type of Windows operating system you are running, read this guide to find that out. 

download and install updates manually

That's it, we hope this guide was helpful and you were able to fix the Windows Update error "0x80070643" by applying one of our described methods. If there is another method that solves this problem for you and it is not mentioned in our guide - do not hesitate to share it with us and with the others by leaving a comment in our comment section below.

[Back to Table of Contents]

Video Showing How To Fix Windows Update Error 0x80070643:

[Back to Top]

About the author:

Tomas Meskauskas

I am passionate about computer security and technology. I have an experience of 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an editor for since 2010. Follow me on Twitter to stay informed about the latest tech news or online security threats. Contact Tomas Meskauskas.

Our guides are free. However, if you want to support us you can send us a donation.