Windows Update: Fix error 643

Error 643 or 0x643 occurs in connection with Microsoft .NET (or the .NET Framework) and reports that the MSI software update registration is incorrect. This system component is required for some programs to run correctly and is usually kept up to date via Windows Update. You will receive the error code when .NET cannot update correctly. There can be various reasons for this.

1. Click on the Start button and open the Settings .
2. Select Update & Security , then switch to the Troubleshooting area.
3. Click Additional troubleshooters and then click Windows Update > Run troubleshooter .
4. Follow the further on-screen instructions to complete the repair.

If you couldnt fix the problem using these methods, you need to repair Microsoft .NET:

1. Download and launch the free “ Microsoft .NET Framework Repair Tool “.
2. Confirm that you have read the license terms and click Next .
3. After analysis, the tool suggests changes that could fix the problem. Confirm this suggestion by clicking Next .
4. Leave the repair tool open and try to install Windows Update again. If the update was successful, you can close the tool. Otherwise, click on Next again and follow the instructions in the wizard.

If error 643 still occurs when running Windows Update, you can also install Microsoft .NET manually:

1. Download the latest version of Microsoft .NET from Chip.de or directly from Microsoft .
2. Launch the downloaded file and follow the installer instructions. Components already present on the PC are automatically updated.
3. If you have already installed the latest version of Microsoft .NET on your PC, click on the Repair button after starting the installation program. Alternatively, select the Uninstall option and then start the installation from the beginning.

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