Solutions to .Net Framework Update Error 643

When you use Windows Update to update your computer, you may get below error suddenly:

Security Update for Microsoft .NET Framework, Version 1.1 Service Pack 1 (KB886903)

Installation date: ‎10/‎11/‎2007 3:10 AM

Installation status: Failed

Error details: Code 643

This error can happen to different updates that related to .net framework, for example, .net framework 2.0, .net framework 3.0, .net framework 3.5. This errors can be caused by two reasons:

.NET Framework installation is corrupt.
MSI database is in an inconsistent state.

To solve these two problems, What you have to do is either to reinstall the .net framework or repair the MSI database. It is simple for you to repair your MSI database, because Microsoft company has already released a repair tool, you can download from here to repair your MSI database.

To restore the corrupted .net framework version is relatively more complicated. You will have to remove the old files and entries that are installed in your computer, and replace with new ones. To do this:

First, go to control panel, click add and remove programmes.
Second, find all the .net framework versions and click to unsintall them.
Third, download the install files from Microsoft download center and install them in your computer.

NOTE: Remove .net framework from control panel may lead to incomplete removal and may leave some registry files in the system that block the reinstallation. To ensure that the old versions are completely removed, we suggest you use a reliable tool such as Smartpcfixer to uninstall and remove the entries.

After you remove all entries and files of your .net framework, you can download and reinstall them from below:

If above suggestions did not help you to resolve the issue, there may be more serious errors in your system. It is highly recommended that you use a registry fixer to scan and fix the errors for you. After that, you shall have no problem in updating your windows.