Error codes “0x80070643” or “0x643” occur when you install the .NET Framework updates

When you try to install updates for the .NET Framework by using Windows Update, Microsoft Update, or an update to the .NET Framework, you may receive an error that has one of the following error codes:

This issue may occur if the MSI software update registration has become corrupted, or if the .NET installation on the computer has become corrupted.

To troubleshoot this issue, try to fix the MSI software update registration corruption issues by using the steps in method 1. If that doesn't work, repair the .NET Framework by using the steps in method 2.

Method 1: Fix MSI software update registration corruption issues

To fix MSI software update registration corruption issues automatically, click the Fix it button or link. Click Run in the View Download dialog box, and then follow the steps in the Fix it wizard.

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Note This wizard may be in English only, but the automatic fix also works for other language versions of Windows.

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Note If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD or DVD, and then run it on the computer that has the problem.

For more information about how to fix this issue, see the following article in the Microsoft Knowledge Base: Visit Windows Update, and and then try to install the updates again. Or, update Microsoft Security Essentials. For more information about how to update Microsoft Security Essentials, see Install the latest Microsoft Security Essentials definition updates (http://www.microsoft.com/security/portal/definitions/howtomse.aspx) .

If the issue is not resolved, go to method 2.

Method 2: Repair the .NET Framework

Repair the version of the .NET Framework that did not update.

.NET Framework 4

Follow these steps if you are running Windows Vistaor Windows 7:

1. Close all applications.
2. Click Start, type Uninstall in the Search box, and then click Uninstall a program.
3. Double-click Microsoft .NET Framework 4 Client Profile.
4. Select Repair .NET Framework 4 Client Profile to its original state, and then click Next.
5. When the repair is complete, click Finish.
6. Click Restart Now to restart your computer.
7. When your computer is restarted, click Start, type Windows Update in the Search box, and then click Windows Update to install the latest Windows updates.

Follow these steps if you are running Windows XP:

1. Close all applications.
2. Click Start, click Control Panel, and then click Add or Remove Programs.
3. Click Microsoft .NET Framework 4 Client Profile in the list of installed programs, and then click Change/Remove.
4. Select Repair .NET Framework 4 Client Profile to its original state, and then click Next.
5. When the repair is complete, click Finish.
6. Click Restart Now.
7. After the computer restarts and you log on to Windows, click Start, type Windows Update in the Search box, and then click Windows Update.
8. Click Check for updates. After the scan is complete, click Install Windows Updates, and then follow the instructions.

.NET Framework 1.0, 1.1, 2.0, 3.0, 3.5

To repair the .NET Framework 1.0, 1.1, 2.0, 3.0, 3.5, 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. Visit the following blog post:
   .NET Framework Cleanup Tool User's Guide (http://blogs.msdn.com/b/astebner/archive/2008/08/28/8904493.aspx)
2. Download dotnetfx_cleanup_tool.zip from the following site:
   http://blogs.msdn.com/cfs-file.ashx/__key/CommunityServer-Components-PostAttachments/00-08-90-44-93/dotnetfx_5F00_cleanup_5F00_tool.zip (http://blogs.msdn.com/cfs-file.ashx/__key/CommunityServer-Components-PostAttachments/00-08-90-44-93/dotnetfx_5F00_cleanup_5F00_tool.zip)
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 a 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.
   
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   Note This tool may be in English only, but it also works for other language versions of Windows.
6. Click Yes to accept the license agreement.
7. In the Product to cleanup window, click the drop-down list, select a .NET Framework version that you want to remove, and then click Cleanup Now.
   
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   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:
   .NET Framework 1.1
   
   Microsoft .NET Framework Version 1.1 Redistributable Package (http://www.microsoft.com/downloads/details.aspx?FamilyID=262d25e3-f589-4842-8157-034d1e7cf3a3)
   
   .NET Framework 1.1 Service Pack 1 (SP1)
   
   Microsoft .NET Framework 1.1 Service Pack 1 (http://www.microsoft.com/downloads/details.aspx?familyid=A8F5654F-088E-40B2-BBDB-A83353618B38)
   
   .NET Framework 3.5 SP1 (this will also install the .NET Framework 2.0 SP2 and the .NET Framework 3.0 SP2)
   Microsoft .NET Framework 3.5 Service Pack 1 (http://www.microsoft.com/downloads/details.aspx?familyid=AB99342F-5D1A-413D-8319-81DA479AB0D7)
10. Restart the computer.
11. Visit Windows Update again, and then check for and install updates.

Known Issues

You may also encounter the following issues when you try to install this update:

• The update is not installed.
• The system keeps reminding you to install this update even though you already installed it.
• The desktop does not appear.

If you encounter one of the issues mentioned here, try the following methods to resolve the issue.

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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.

To do this, click to follow the steps in the following article:If you receive this error with Office Updates, see the following Windows Online article to find a resolution:

If this article does not answer your question, click this button to ask other community members at Microsoft Answers: