How To Fix It: Windows Update 643 bug

  • Windows Update error code 643 is an update error, more common in Windows 7, 8, and 8.1.
  • The error is caused by a corruption in the installation of the.NET Framework or an inconsistent state of the MSI database.
  • There are many causes for the error, and the solutions mentioned below vary depending on the specific scenario.
  • If you have a reliable third-party antivirus program on your computer, it is best to let it do its job without further delay.
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There is a conflict between the .NET framework and software that causes the error code 643 to appear during a Windows update.

Despite being a platform that is constantly evolving, Windows 10 has continuously improved its overall performance. It consists of features that make it easier to use, and security features that protect it from malicious attacks.

The error code 643 is a common update error that some users report when trying to install Windows updates on forums. It is more frequent in Windows 7, 8, and 8.1 and stops Windows from updating. There are a few ways to fix error code 643.

In addition to Windows Update error code 643, you might also encounter conflicts between software and the .NET framework, which can result in the error.

Windows 7 is one of the most loved operating systems released by Microsoft. Even though official support for it is going down in 2020, there are still many users that prefer and use it till this day. There are still updates released for Windows 7 which makes it even more competitive performance and features wise. However, in some case, you might come across some errors while trying to initiate an update. One of these errors is error code 643. This error is very generic and tends to come up now and then for someone. This is mainly caused by .NET framework corruption. That, however, is not the only cause it is restricted to i.e it can also be caused by software conflicts. We will be discussing the causes of the error code in more detail down below.  The error mainly occurs in Windows 7 but can occur in Windows 8 and 8.1 as well. Due to this error, your Windows will not update and you will not be able to get updates from Microsoft.

It is always recommended to update your Windows 10 operating system regularly to ensure that your computer runs smoothly and flawlessly. However, some users have reported that an update error code 643 occurred while installing Windows Update. Specifically, you may receive a Windows Update error code 0x643 or 0x80070643 when trying to install an update for .NET Framework. This error code is usually caused by a corruption in the installation of the .NET Framework or an inconsistent state of the MSI database.

You may not be able to update Windows Update because of this error code, which may eventually result in its inability to function.

An unknown error occurred while updating Windows.

A few people report that they receive error code 643 when trying to perform a Windows update. Windows update error code 643, also known as update error, occurs most commonly in Windows 7, 8, and 8.1. Here are some solutions that can fix error code 643.

What causes error code 643 in Windows Update?

What causes error code 643 in Windows Update?

There are usually several reasons why error code 643 appears. These include:

Error code 643 generally occurs when a system update cannot be installed for some reason, such as:

Third-party antivirus program interference: an error code may appear because a third-party antivirus program on your system is interfering with the update process. In this case, you need to temporarily disable the antivirus software and then run its update.

In many cases, error code 643 is caused by an incorrectly installed version of Microsoft’s NET Framework. You can fix NET Framework by downloading the Microsoft NET Framework tool. Click the I accept the license terms box in the utility’s window, and then click Next.

The .NET Framework is corrupted: The main cause of the error seems to be corruption during the installation of the .NET Framework. In this case, you need to uninstall the various versions of the .NET Framework using a utility, and then reinstall it.

It is possible to get rid of this error in many ways. It is important to note that the error can be caused by a variety of factors, and the solution will depend on your specific situation. You can try the following solutions. Depending on the cause of your problem, we hope one of the solutions will work for you.

How to fix Windows Update error code 643

Updated: December 2023

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How to fix Windows Update error code 643

Your security solution should be disabled

To fix the error code 643, you first need to temporarily disable your third-party antivirus program. Third-party security tools often conflict with Windows Update, resulting in the error code 643. You should contact your antivirus vendor if that solves your issue, or switch to another antivirus product if that does not.

Check your computer for malware

Attackers are very interested in targeting Windows Update.
You may have malware on your computer if you see Windows Update error 643 in Win 7.
Since your system might be compromised, you should scan it immediately.

It is advisable to let a third-party antivirus software do its job as soon as possible if you have one installed on your computer.

The Windows Defender software can prove whether Microsoft products are the best at fighting malware:

Launch Windows Defender > click Scan and then type “Defender” in the search field.

It gives me a message that the .NET Framework update KB4535102 cannot be installed (update error 643) when I run Windows Update. Do you have any idea how I can fix this?

Anti-malware tools are essential for keeping your computer safe from harmful software.

Troubleshooting Network Problems

It is possible that your network is experiencing problems if you keep getting the Windows Update 643 error.

Fixing them is as simple as:

  1. Go to the Start menu, select Control Panel, then select Network and Internet from the left hand menu.
  2. Then select the “Fix Network Problem” option in the Network and Sharing Center.
  3. To repair your network, use the functions in the Network Troubleshooting Guide

Make sure to update your network card driver

Your network adapter’s driver may be out-of-date, so it’s imperative you update it immediately if the previous method didn’t work.

It is possible to automate this process using the Windows Device Manager:

  1. Then right-click the “Computer” item in the Start menu.
  2. “Manage” will appear from the menu options; click on it to open the computer management screen.
  3. Then select your network adapter from Device Manager, right-click on it, and click on Update Driver Software.

Your driver may not be updated by the Device Manager. If this happens, bad things could happen.
It won’t take you long to find your preferred version online. Alternatively, you can use a third-party tool to speed up the process.

Microsoft’s “Fix It” tool is a good option.

To fix the Windows Update 643 error, download the Microsoft Fix It wizard from Microsoft’s official website and follow the wizard’s instructions.

Uninstall Microsoft.Net Framework 4 client profile.

In Windows 7, you can uninstall Microsoft.Net Framework 4 client profile if it has been corrupted. Here’s how to do it:

  1. Select “Start Menu”, then “Control Panel”, then “Programs and Features”.
  2. A client profile of Microsoft.Net Framework 4 should be found and it should be uninstalled
  3. Ensure Windows Update is running and restart your computer.

Reset Windows Update components

In order to use this method, you will need to open the extended order prompt. Follow the steps below:

  1. Type “cmd” (without quotes) into the “Run” window after pressing Windows logo + R.
  2. “Cmd” can be found by right-clicking it and selecting “Run as administrator”

To get started, type the following commands (after each command, press Enter):

Bits for shutdown of networks
Shut down Wuauserv
Application for net-stopping
Delete “%ALLUSERSPROFILE%ApplicationDataMicrosoftNetworkDownloaderqmgr”.
Copy the system32 folder to %windir%
Atl.dll, registry32.exe
The regsvr32.exe file and mshtml.dll file are required to run
exe regsvr32 dll shdocvw
File: regsvr32.exe/browseui.dll
It is located in the following files: regsvr32.exe, jscript.dll
Vbscript.dll vsvr32.exe
Scrun.dll is the replacement for regsvr32.exe
The registry, regsvr32.exe, and the MsXML.DLL files
Msxml3.dll msvr32.exe
Regsvr32.exe and Msxml6.dll
Regsvr32.exe, dll Actxprxy
Register32.exe, Softpub.dll
Registrer32.exe, Wintrust.dll
In the registry, you can find the file dssenh.dll by searching
The RSAENH.DLL file is opened by regsvr32.exe
The gpkcsp.dll file and regsvr32.exe file
SCCbase.dll svr32.exe
Dlls, regsvr32.exe, slbcsp.exe
Regsvr32.exe and Cryptography.dll
A registersvr32.exe and an ole32.dll file
Registry32.exe Shell32.dll
DLL initpki.exe
A registry lock file wuaueng.dll is loaded by regsvr32.exe
A file called regsvr32.exe is required to run wuaueng1.dll.
A registry file wucltui.dll is run by regsvr32.exe
Regsvr32.exe and WUPS.dll
A file named regsvr32.exe and a file named wups2.dll are required
Regsvr32.exe and Wuweb.dll
Regsvr32.exe and QMGR.DLL
Registry32.exe, QMGRXY.dll
The registry file is wucltux.dll.
DLL: muweb.dll/regsvr32.exe
In Winsock, reset the grid
Proxy reset for winhttp
Bits used in networking
WUA service is starting on the network
Applications that are easy to start with PVC
Cryptogram for launching

Close the order prompt once you have received the green indicator to continue. You should now be able to visit your Windows Update Center. Download the Windows Update Agent from Microsoft support. Install it on your computer. Then reboot. Now you should have access to the Microsoft Update Center.

Resolving the system registry

You may need to replace the registry if your efforts have been in vain.
If you modify the registry, you run the risk of causing Windows 7 to fail or even malfunctioning. It is important to note that even a small error can cause a severe problem or even cause the system to fail. The vast majority of people believe such a result is unacceptable. To safely and effectively restore your Windows registry, we recommend using a special tool. You can do this for free with a third-party program, for example.

Resetting the system to an earlier state

The only way to accomplish this is to use System Restore. When enabled, you can use this feature to restore the Windows 7 operating system to an earlier date, undoing any changes you’ve made.

  1. The Start menu can be accessed by clicking it; then you can find the System Restore option by searching for it.
  2. You can do this by clicking System Restore and then selecting the option to restore system files and settings; then clicking Next.
  3. Ensure the last restore point you made before having the Windows 643 update error was the last one that did not have the issue > Confirm

RECOMMENATION: Click here for help with Windows errors.

Most Frequently Asked Questions

  1. Run the Windows Update diagnostic.
  2. Run the SFC scan.
  3. Remove the software distribution folder.
  4. Disable updates for other Microsoft products.
  5. Remove problematic updates.
  6. Manually download and install Windows updates.

  1. Use System File Checker and DISM.
  2. Run the Microsoft Windows Update online diagnostic tool.
  3. Disable antivirus or firewall.
  4. Disable proxy or VPN.
  5. Reset the Windows Update folders.
  6. Reset Windows Update components.

  1. Open the settings.
  2. Click Update and Security.
  3. Click Troubleshooting.
  4. Under Start and Run, select Update Windows.
  5. Click Run Troubleshooter. Source: Windows Central.
  6. Click the "Close" button.

  • Run the Windows Update troubleshooter.
  • Restart the services related to Windows Update.
  • Run the System File Checker (SFC).
  • Run the DISM command.
  • Temporarily disable your antivirus program.
  • Restore Windows 10 from a backup.

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Mark Ginter is a tech blogger with a passion for all things gadgets and gizmos. A self-proclaimed "geek", Mark has been blogging about technology for over 15 years. His blog,, covers a wide range of topics including new product releases, industry news, and tips and tricks for getting the most out of your devices. If you're looking for someone who can keep you up-to-date with all the latest tech news and developments, then be sure to follow him over at Microsoft.