Error Code: 643 (Can't install KB951847)

I have also same problem I try Zhao's solution and let you know the results I hopa it will work...

Just finished with this and it worked!!  Have trying for 3 days to install this update.

I have Windows XP with SP3 installed,

Thanks William Zhao!!!

I received the following Microsoft fix today.

I have been receiving instructions from a Microsoft Tech since last Thursday.

Some of you are likely seeing a Windows Update icon in your system tray right now. DONOT download those updates until you have done the following listed below.

Be sure to follow the instructions carefully. This fix repaired my problem and I was able to download all the new .net framework security updates successfully.

This applies to those using Windows XP and it repaired the problem:

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I understand that the following 2 updates still cannot be installed. The error code 0x645 is received.

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Microsoft .NET Framework 2.0 Service Pack 2 Security Update for Windows 2000, Windows Server 2003, and

Windows XP (KB974417)

Microsoft .NET Framework 3.5 Service Pack 1 and .NET Framework 3.5 Family Update for .NET versions 2.0 through 3.5 (KB951847) x86

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In order to narrow down the cause of this issue and resolve it, please refer to the following steps.

 

Step 1: Use .Net Framework CleanUp Utility

============================================

1. Please download the .NET Framework Cleanup Tool from the following link:

 

http://windowsuu.com/tools/dotnetfx\_cleanup\_tool.zip

 

Please Note: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

 

2. Unzip the file and then close all the open windows.

 

3. Double click Cleanup_tool.exe to run it, and then select the .Net Framework 2.0 in the list box. Click “OK”, click “Yes”, and click “Cleanup Now” to remove it completely. After that, please also remove the .NET 3.5.

 

Step 2: Reinstall .NET Framework Version 2.0, 3.5 and their updates

==================================================

Please download and install the following updates in order.

 

Microsoft .NET Framework Version 2.0 Redistributable Package (x86)

http://download.microsoft.com/download/5/6/7/567758a3-759e-473e-bf8f-52154438565a/dotnetfx.exe

 

Microsoft .NET Framework 2.0 Service Pack 2

http://download.microsoft.com/download/c/6/e/c6e88215-0178-4c6c-b5f3-158ff77b1f38/NetFx20SP2\_x86.exe

 

Microsoft .NET Framework 2.0 Service Pack 2 Security Update for Windows 2000, Windows Server 2003, and Windows XP (KB974417)

http://download.microsoft.com/download/A/0/1/A01064A3-CAB0-4851-9C54-56A980FF00EB/NDP20SP2-KB974417-x86.exe

 

After that, please restart the computer and then install Microsoft .NET Framework 3.5 and its update.

 

Microsoft .NET Framework 3.5 and .NET Framework 3.5 Service Pack 1

http://download.microsoft.com/download/2/0/E/20E90413-712F-438C-988E-FDAA79A8AC3D/dotnetfx35.exe

 

Microsoft .NET Framework 3.5 Family Update

http://download.microsoft.com/download/C/6/A/C6ADC586-2518-404B-8973-E1E22C556AF4/NDP35SP1-KB958484-x86.exe

 

Note: When the file download window appears, please click "Save", and follow the directions to save it on the Desktop. After downloading the setup file on your Desktop, double-click to manually install it.

 

However, if any error is encountered when installing, please capture a screenshot of the error message:

 

How to capture a Screenshot:

======================

1. When the error appears, please press the "Print Screen" key (PrtScn) on your keyboard.
2. Click "Start", click "Run", type MSPAINT, and click "OK".
3. In Paint, click "Paste" under the "Edit" Menu, click "Save" under the "File" menu, type a file name for the screenshot, choose JPEG as "Save as type", click "Desktop" on the left pane, and click "Save".
4. Please find the screenshot on the Desktop and send it as an attachment to: *** Email address is removed for privacy ***.

 

Please try my suggestions and let me know the results at your earliest convenience. If you have any other questions, please do not hesitate to let me know.

 

I look forward to your response.

 

Best Regards,

 

William Zhao

*** Email address is removed for privacy ***

Microsoft Windows Update Support Professional

Thank you for your reply.

I have performed these steps and they did not repair the problem.

As such, I have unproposed your post as answer.

Thank you for your input anyway, it might work for others.

PS: You should not post e-mail addresses on the Internet, especially if they are not yours. Please edit your post and delete any e-mail addresses. Thank you.

I didn't post a private e-mail address. I posted a public e-mail that belongs to Microsoft in a Microsoft forum. Microsoft Mods have already read it and recommended it...so thank you too.

Very nice for those with XP but I am on Vista with a brand new Toshiba laptop computer bought 3 weeks ago. I have been trying to install that update for at least 2 weeks but I keep getting an error message that install failed.

Please help before I go crazy.

Marc

These steps are applicable to Vista as well.

I had Vista as well and I performed these steps successfully, although they didn't fix the issue.

If they don't work for you either, I recommend you to either contact Microsoft Support free of charge (https://support.microsoft.com/oas/default.aspx?&c1=509&gprid=6527&&st=1) or perform a Vista Repair Install.