.NET Framework update installation error: "0x80070643" or "0x643"

Support for Windows XP has ended

Microsoft ended support for Windows XP on April 8, 2014. This change has affected your software updates and security options. Learn what this means for you and how to stay protected.

This issue may occur if the MSI software update registration has become corrupted, or if the .NET Framework installation on the computer has become corrupted.
To resolve this issue, try one or more of the following methods in the order they are listed.

Note This article does not apply to Windows 8 or later.

Method 1: Repair the .NET Framework
Download the Microsoft .NET Framework Repair Tool to repair the following versions of the .NET Framework, and then reinstall the .NET Framework update:
  • The .NET Framework 4
  • The .NET Framework 3.5 SP1
  • The .NET Framework 3.0 SP2
  • The .NET Framework 2.0 SP2
For more information, see Version 2 of the Microsoft .NET Framework repair tool is available. If the issue is not resolved, or if you are using other versions of the .NET Framework, go to method 2.  
Method 2: Uninstall and reinstall the .NET Framework
Use the .NET Framework Cleanup Tool to uninstall multiple versions of the .NET Framework, and then reinstall the components.

To do this, follow these steps:
  1. Check out the .NET Framework Cleanup Tool User's Guide.
  2. Download the .NET Framework cleanup tool.
  3. When you are prompted, click Open, and then click Extract Now.
  4. In the files that you extracted, double-click cleanup_tool.exe.
    If you are prompted for an administrator password or for confirmation, provide the password, and then click Continue.
  5. In the Do you want to run the .NET Framework Setup Cleanup Utility? message, click Yes.
  6. Click Yes to accept the license agreement.
  7. In the Product to cleanup window, click the list, select .NET Framework - All Versions, and then click Cleanup Now.
    Note The cleanup tool does not let you remove the .NET Framework 2.0 in Windows Vista or later versions of Windows because the .NET Framework is installed as an operating system component.
  8. After the .NET Framework is removed, restart the computer.
  9. Download and install the following components:
    The .NET Framework 1.1

    The .NET Framework 1.1 Service Pack 1 (SP1)

    The .NET Framework 3.5 Service Pack 1 (this will also install the .NET Framework 2.0 SP2 and the .NET Framework 3.0 SP2)
  10. Restart the computer.
  11. Visit Windows Update again, and then check for and install updates.
  12. Try to reinstall the .NET Framework update.
More information
Other .NET Framework update installation issues
You may also experience the following issues when you install .NET Framework updates:
  • The update is not installed.
  • The system keeps reminding you to install this update even though you have already installed it.
  • The desktop does not appear.
Resolution to these installation issues
If you experience one of these issues, try the following methods to resolve the issue.

Method 1: Download the update from the download link and install it in clean boot mode 

We suggest that you install the updates in clean boot mode to avoid interrupting non-Microsoft programs. To enter clean boot mode on a computer, follow these steps:
  1. Click the Start button, type msconfig in the Start Search box, and then press Enter. If you are running Windows 8 or Windows 8.1, type msconfig on the Start screen, and then press Enter.
  2. If you are prompted for an administrator password or for confirmation, type the password or click Continue.
  3. On the General tab, click Selective Startup.
  4. Under Selective Startup, clear the Load Startup Items check box.
  5. Click the Services tab, click to select the Hide All Microsoft Services check box, and then click Disable All.
  6. Click OK.
  7. When you are prompted, click Restart.
  8. After your computer restarts, try to update your computer again.
For more information about this method, see the following article in the Microsoft Knowledge Base:
331796 Perform a clean startup to determine whether background programs are interfering with your game or program
If you are not installing the .NET Framework updates when you receive error code 0x80070643 or 0x643, you may have to collect additional logging information to troubleshoot your issue. These logs can be reviewed by support professionals or IT professionals to help determine the issue.

If you receive this error when you install Office updates, see Windows Update error 80070643 for solution.

Article ID: 976982 - Last Review: 08/05/2016 06:30:00 - Revision: 41.0

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