‘Perfection is a polished collection of errors’
Mario Benedetti

These days it is a must for everyone to keep their Windows OS up to date. Otherwise, it is practically impossible to ensure its smooth running. The sad thing is, in reality, things are not that simple: persistent Windows Update errors often spring up out of the blue and prevent desirable updates from entering your computer. This, in turn, exposes your system to numerous risks and may eventually render it unusable.

Windows Update Error 643, which occurs mostly in Windows 7, is a case in point. You can run into the Windows Update error code 643 due to many reasons: software conflicts, malware infection, registry issues, and corrupted files are chief among them.

Luckily, the problem in question can be easily fixed. Just work your way through the solutions below:

1. Turn off your security solution

To begin with, you should temporarily disable your third-party antivirus. The point is, non-Microsoft security tools often come in conflict with Windows Update, which may result in the annoying Windows Update error code 643. If this manoeuvre has fixed your problem, you should contact your vendor or switch to another antivirus product.

2. Scan your PC for malware

Unfortunately, Windows Update is a highly coveted target for malicious attackers. As such, Windows Update Error 643 in Win 7 can be a sign that your computer is malware-infected. Therefore, you should scan your system as soon as possible, since it may be compromised.

If you have a reliable third-party antivirus installed on your PC, you are better off letting it do its job without further delay.

Those who believe that Microsoft products are second to none in anti-malware protection should run a scan with Windows Defender:

Start -> Type ‘Defender’ into the Search box -> Windows Defender -> Scan

And to make sure no hostile software whatsoever is lurking around in the background, you should make use of a powerful anti-malware tool such as Auslogics Anti-Malware.

3. Troubleshoot your network

If Windows Update Error 643 persists, you may be experiencing network issues.

Here is how you can troubleshoot them:

  1. Open Start menu -> Go to Control Panel -> Move to Network and Internet
  2. Enter your Network and Sharing Center -> Select Fix a Network Problem
  3. Now you are in Troubleshooting guide for the network -> Use its features to fix your network

4. Update your network adapter driver

If the previous method has been of no use whatsoever, your network adapter driver may be out of date, which means you should find and install the latest version of it straightaway.

Windows Device Manager can do that automatically:

  1. Open your Start Menu -> Right-click on Computer
  2. Select ‘Manage’ from the list of available options -> The Computer Management screen will open
  3. Go to Device Manager -> Locate your network adapter and right-click on it -> Update its driver software

Unfortunately, Device Manager may fail to update your driver. Bad things happen, you know. Nevertheless, there is no need to worry: you can either perform the trick yourself by searching the web for the version you need or use Auslogics Driver Updater to shave some time off this tedious process – in fact, this tool will fix all your driver issues in just one click.


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Unstable PC performance is often caused by outdated or corrupt drivers. Auslogics Driver Updater diagnoses driver issues and lets you update old drivers all at once or one at a time to get your PC running smoother

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5. Use the Microsoft Fix It tool

If you have made this far, it is time ask good old Microsoft Support for some help. Go to its official website and download the Microsoft Fix It wizard. Use its prompts to troubleshoot your Windows Update Error 643.

6. Uninstall Microsoft.Net Framework 4 Client Profile

And here is another reportedly effective fix: your Microsoft.Net Framework 4 Client Profile may be corrupt, which means you should uninstall it. Here is how to do that in Windows 7:

  1. Start Menu -> Control Panel -> Programs -> Programs and Features
  2. Locate Microsoft.Net Framework 4 Client Profile -> Uninstall it
  3. Restart your PC -> Try to update your system, using Windows Update

7. Reset the Windows Update components

This method implies using your elevated command prompt. To open it, do the following:

  1. Press Windows logo key + R simultaneously to open the Run box -> Type ‘cmd’ (no quotes) -> Enter
  2. Locate ‘cmd’ and right-click on it-> Select the Run as Administrator option

Now you should type the following commands below (make sure to hit Enter after each):

net stop bits
net stop wuauserv
net stop appidsvc
net stop cryptsvc
Del “%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat”
cd /d %windir%\system32
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
netsh winsock reset
netsh winhttp reset proxy
net start bits
net start wuauserv
net start appidsvc
net start cryptsvc

After getting the all-clear to proceed, close your command prompt. Go to the Microsoft Support website and download the latest version of Windows Update Agent. Install it on your computer. Then restart your PC. Now visit your Windows Update center – it is supposed to work well now.

8. Fix your system registry

All to no avail? Then you should consider editing your registry: it might be corrupt or damaged. What you should keep in mind is that modifying your system registry is an extremely risky procedure – even a tiny error can get you a nice case of malfunction or even cause your Windows 7 to go haywire. We believe, as do most people, that this kind of outcome is totally undesirable. That is why we recommend you to employ a special tool to fix your Windows registry in a safe and effective way. For instance, Auslogics Registry Cleaner will do that for free.

9. Configure your system to an earlier state

For this purpose, you are supposed to make use of the System Restore feature: if it is enabled, you can take your OS to an earlier date and undo recent system changes.

Just follow the instructions below to use System Restore in Windows 7:

  1. Open your Start menu -> Navigate to the Search box -> Type System Restore into it
  2. Go to System Restore -> Select the Restore system files and settings option -> Click Next to proceed
  3. Select the most recent restore point at which your OS was not experiencing Windows Update Error 643 -> Provide your confirmation

We hope your Windows Update is up to the mark now.

Do you have any ideas or questions regarding this issue?

We are looking forward to your comments!