Fix the Windows Update Error 0x80070643 (Windows Defender)

Users complain that the Windows Defender update fails to install due to the 0x80070643 error code. The error is likely caused by malware, file corruption, driver malfunction, or even improper system settings.

The full error message states: There were problems installing some updates, but we’ll try again later. If you keep seeing this, and want to search the web or contact support for information, this may help. Definition Update for Windows Defender – Error 0x80070643.

If you encountered the 0x80070643 error on Windows 11, check out our dedicated guide for more help.

How do I fix the Windows Defender 0x80070643 error?

1. Use antivirus removal tools

When you uninstall a third-party antivirus using the Uninstall option from Control Panel, some files might remain undetected, preventing you from running and updating Windows Defender.

Even if you uninstalled your previous antivirus and have been using Windows Defender for quite some time without any problems, you’re not safe.

The remnants of your previous antivirus may now be causing the 0x80070643 Windows Defender error, and since they are hard to remove manually, you need to deal with them some other way.

This is where uninstaller software comes in handy to remove your antivirus or any leftover files. It is specially designed to remove the selected application and all its files and registry entries, leaving a clean space.

Completely uninstall your old antivirus programs, restart your computer, and Windows Defender should be able to install the latest updates.

2. Check your system files

1. Press Windows Key + X and choose Command Prompt (Admin) from the menu.
2. You can also use PowerShell (Admin).
   
3. Type the following command and hit Enter: sfc /scannow
   

The System File Checker tool repairs corruption in system files. Use this tool to verify whether Windows Defender is corrupted, which could explain why you can’t install the updates.

To perform an SFC scan, you need to do the following:

If you can’t run the SFC scan or if SFC didn’t solve the problem, you might have to use a DISM scan instead. To do that, follow these steps:

1. Start Command Prompt as administrator.
2. Now run the following command and press Enter: DISM /Online /Cleanup-Image /RestoreHealth
   
3. DISM scan will now start.
4. Remember that this scan can take up to 20 minutes or more, so don’t interrupt it.

Once the DISM scan is finished, check if the problem is resolved. If the issue persists, or if you couldn’t run an SFC scan before, try rerunning the SFC scan and check if that solves the problem.

3. Perform a Clean boot

1. Press the Windows Key + R and enter msconfig.
2. Press Enter or click OK.
   
3. The System Configuration window will now appear.
4. Go to the Services tab and check to Hide all Microsoft services.
5. Now click Disable all button.
   
6. Go to the Startup tab and click Open Task Manager.
   
   • A list of startup applications will now appear.
7. Please select the first item on the list, right-click it and choose Disable from the menu.
8. Now repeat this step for all startup applications.
   
9. Once you disable all startup applications, close Task Manager and return to the System Configuration window.
10. Click Apply and OK to save changes and restart your PC.
    
11. Once your PC restarts, check if the problem still appears.
    • If not, go back and enable disabled apps and services one by one until you find the one causing the issue.
12. When you find it, delete or disable it, and the problem will be permanently resolved.

Third-party applications can sometimes interfere with Windows and cause Windows Defender update to fail and the Windows Update error 0x80070643 to appear. You might be able to fix it by performing a Clean boot.

4. Use a third-party antivirus software

If you want to avoid all the problems related to Windows Defender, you can switch to a better security tool, such as third-party antivirus software.

Not only will this software do a better job at protecting your data from being stolen or stopping any virus from infecting your device. It should also have no errors or glitches.

You will also benefit from other useful features that protect your PC and allow you to browse the internet carelessly and without worry.

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5. Restart the Security Center Service

1. Press Windows key + R and launch run.
2. Type services.msc and hit Enter.
   
3. In the Services tab, search for Security Center.
4. Right-click on Security Center, then click on Restart.
   

6. Perform a final manual update

1. Go to Microsoft’s Malware Protection Center portal.
2. Follow the instructions to download and install the Antimalware, antispyware updates, and Network Inspection System updates available for your system.

NOTE

The manual ADL packageu00a0update installs silently. To ensure the manual update worked correctly, check with the Windows Defender Client UI to see if it reports the latest threat definition version.

7. Disable .NET Framework

1. Press the Windows Key + S and enter features.
2. Select Turn Windows features on or off.
   
3. When the Windows Features window opens, disable Windows Communication Foundation HTTP Activation and Windows Communication Foundation Non-HTTP Activation.
4. Now click OK to save the changes.
5. Restart your PC and check if the problem is solved.

According to people, sometimes .NET Framework can cause problems with Windows Defender updates. However, you might be able to fix this problem simply by disabling it.

Several users suggest repairing your .NET Framework installation as a potential solution, so you might want to try that as well.

8. Check for updates from Windows Defender

1. Press Windows Key + I to quickly open the Settings app.
2. Go to the Update & Security section.
   
3. In the left pane, select Windows Defender and then click the Open Windows Defender Security Center button.
   
4. Then, go to Virus & threat protection section.
   
5. Now go to Protection updates.
   
6. Click the Check for updates button.
   

Windows Defender will now download the available updates. In addition, several users reported that this method fixes the kb2267602 error 0x80070643 for them, so feel free to try it out.

If you’re having problems with downloading updates, you might be able to fix the problem by trying to download updates directly from Windows Defender.

9. Reset Windows Update components

1. Start Command Prompt as administrator.
2. Now enter the following commands:
   net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
ren C:WindowsSoftwareDistribution SoftwareDistribution.old ren C:WindowsSystem32catroot2 Catroot2.old
net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Sometimes there might be a bug with Windows Update components, which can cause the Windows Update error 0x80070643 error to appear. You might be able to fix the problem by running several CMD commands.

By running these commands, you’ll stop all services associated with the Windows Update, rename the affected directories and then restart the services. This is a simple solution, so feel free to try it out.

What are some common Windows Defender issues?

Windows Defender offers solid protection, but if you want to keep your Windows 10 PC protected, it’s important to update Windows Defender regularly.

Unfortunately, update issues can occur, and speaking of cases, these are some of the common problems that users reported:

• Windows Defender update failed – If the Windows Defender update fails, the issue might be a third-party antivirus tool. If your previous antivirus isn’t completely removed, sometimes leftover files can interfere with Windows Defender and cause this issue to appear. To fix it, remove any leftover files.
• Windows Defender update stuck – Sometimes, your Windows Defender can get stuck during the update process. If this happens, be sure to repair your system files using both SFC and DISM scans.
• Windows Defender update connection failed – If you get this error message while trying to update Windows Defender, your third-party firewall might be an issue, so be sure to disable it or uninstall it.
• Windows Defender update won’t install – If the Windows Defender update doesn’t install, the issue might be a problematic application. However, you can fix the problem simply by performing a Clean boot.
• Windows Defender not getting updated / security intelligence update error – Several users claim that Windows Update components can cause this issue, so try resetting them and check if that solves the problem.

We’ve written extensively about Defender update problems before. So bookmark our article on what to do if Windows Defender won’t update in case you need it later.

We hope these fixes work for you in solving the Windows Update error 0x80070643, related to Windows Defender.

If you’ve found other workarounds for the Windows Defender 0x80070643 issue, tell us more about your experience in the comment section below.