It’s always suggested to update your Windows 10 OS regularly so that you can keep operating your computer in a smooth and impeccable way. But some users have reported encountering an update error code 643 while trying to install Windows Update. Specifically, when you try to install an update for the .NET Framework, you may receive Windows Update error code 0x643 or 0x80070643. This error code is usually caused by a corruption in the .NET Framework installation or by an inconsistency in the MSI database state.

This update error code prevents you from updating your Windows update and may ultimately make it unusable. Thee error message can also appear in the following format:

Error(s) found: Code 643 Windows Update encountered an unknown error.

In this guide, we have come with some easy tweaks that may likely help you to fix this error. So let’s get started.

Windows Update Error Code 643

To fix Windows Update Error Code 643, follow these suggestions:

Run the Windows Update Troubleshooter
Repair the Microsoft .NET Framework
Use the Microsoft .NET Framework Cleanup Utility.

Before you begin, create a system restore point first. It will help you to revert the changes if somewhere undesirable appears to happen.

Let us now see how to fix the Error Code 643 in detail.

1] Run the Windows Update Troubleshooter

Windows 10 comes with an inbuilt troubleshooter tool that potentially diagnoses and fixes the common issues related to the Windows update.

In order to fix this error code, you can either run the Windows Update Troubleshooter or use Microsoft’s online troubleshooter method. And then check whether this method works for you.

If you don’t find it useful, move down to the next effective workaround.

2] Repair the Microsoft .NET Framework

Sometimes Windows Update error can also be caused due to the corrupted .NET Framework Client Profile. However, you can repair this profile using the Programs applet in Control Panel.

To do that, follow the below guidelines:

Open the Control Panel
On the Programs and Features page, search for Microsoft .NET Framework.
Once you find, right-click on it and select the Repair or Change option from the menu list.
If UAC prompts on the screen, click on the Yes button and let begin the procedure.

Wait for a while and once it completes the process, reboot your computer, and check whether the error Code 643 is resolved now.

Read: Error 0x800F081F while installing .NET Framework.

3] Use the Microsoft .NET Framework Cleanup Utility

As a last resort, you can reinstall the .NET Framework. Actually, this problem can also occur due to the improper installation of the Microsoft .NET Framework installation. Therefore, clean up Microsoft .NET Framework thoroughly and then reinstall it.

Use the Microsoft .NET Framework Cleanup Utility.

Download it and then navigate to the downloaded location and extract the zip file using the context menu.

Inside the extracted folder, double click on the cleanup_tool executable file. If UAC prompts, simply hit Yes.

At this time, you will be asked to run the .NET Framework Setup Cleanup Utility, click the Yes button.

In the next pop-up menu, select .NET Framework – All Versions (Windows 10) using the drop-down menu.

And then hit the Cleanup Now button. It will thoroughly remove the components related to the Microsoft .NET Framework from your device.

Now moving ahead download the latest version of the .NET Framework and then reinstall it.

After the proper installation, restart your system and then try to perform the Windows Update.

TIP: Microsoft .NET Framework Repair Tool can fix .NET Framework problems & issues.

All the best! Hope you may find this article helpful.

MORE TIPS: Troubleshoot .NET Framework installation issues.