.NET Framework Update Error Code 0x643 & Error Code 1603

Windows update error code 0x643 or Microsoft Windows Installer error code 1603 may occur when you attempt to install an update for different versions of .NET Framework (1.0, 1.1, 2.0, 3.0, or 3.5).

Error code 0x643 and error code 1603 are generic Windows update and Windows installer error codes. When these error codes are generated they imply that the update was not installed.

Cause of the Error

These error codes generate when one of the following is true:

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

Resolution Methods

To resolve this issue, you need to remove all .NET Framework versions from your system and then reinstall them. You can use one of the following methods to do these tasks:

Method 1: Perform manual .NET Framework removal and reinstallation

Step 1: Uninstall .NET Framework

  1. Open Control Panel.
  2. Double-click on the Add or Remove Programs icon.
  3. Browse through the Currently installed programs list and uninstall all versions of .NET Framework installed on your system one by one.
  4. Note: Before proceeding with the removal process, write down the currently installed .NET Framework versions.

  5. After you are done reboot your PC.

To ensure that you completely remove the .NET Framework versions, it is recommended that you use a reliable registry tool, such as RegServe, to clean your registry and remove any orphaned entries. You may also choose to use an efficient third-party program uninstall tool, such as Perfect Uninstaller to completely remove .NET Framework from the PC.

Step 2: Clear the MSI database state for all .NET Framework versions using the Windows Installer CleanUp Utility

  1. Download Windows Installer CleanUp Utility from Microsoft Download Website.
  2. Ensure that you are logged on to your PC with a user account that has administrative rights to the system and then install the Windows Installer CleanUp utility.
  3. Open Start menu, select All Programs, and then select the Windows Install Cleanup command.
  4. In the Windows Installer Clean Up dialog box, select and remove all instances related to .NET Framework.
  5. After you are done reboot your PC.

Step 3: Download and install the .NET Framework version that was previously installed on your system.

  1. Click on the following links to download the respective .NET Framework version.
  2. After the installation is complete reboot your PC.
  3. Finally, you may use Windows Update to check for and download .NET Framework updates on the system.

Method 2: Remove .NET Framework using automatic cleanup tool

If you are unsuccessful with the manual .NET Framework removal method, you may use the automatic cleanup tool to do the task.

This tool removes all shared registry keys and files that are required by different .NET Framework versions on your computer. This is the reason why, to ensure complete and successful removal you must first uninstall the older .NET Framework version and then the newer one. For example, if you have .NET Framework 1.1 and .NET Framework 2.0 installed on your PC, you must first remove .NET Framework 1.1 and then .NET Framework 2.0. You must follow the same sequence while reinstalling.