I cannot install update "Microsoft .NET Framework 3.5 Service Pack 1 and .NET Framework 3.5 Family Update (KB951847) x64". Windows Update encounters a reportedly unknown error code 643 and the update fails. How can I fix this? PS: I am running Microsoft Windows Vista 64-bit (ENU) with Service Pack 2 (SP2) on an HP Pavilion dv5-1199eg Entertainment Notebook PC.

Issue fixed on 27-08-2009 by installing Microsoft Windows 7.

I also have the same issue, and have followed all instructions (1) reset MSI service to run as an administrator, (2) Per the Windows Installer Cleanup utility package, there are no versions of .NET installed on my Vista SP2 64bit system, (3) Successfully executed the .NET framework cleanup utility and (4) the installer for the standalone .NET 3.5 package fails with the errors: [09/03/09,12:36:57] Microsoft .NET Framework 3.5 (x64) 'package': [2] Error: Installation failed for component Microsoft .NET Framework 3.5 (x64) 'package'. MSI returned error code 1603 [09/03/09,12:37:16] WapUI: [2] DepCheck indicates Microsoft .NET Framework 3.5 (x64) 'package' is not installed. [09/07/09,19:39:28] Microsoft .NET Framework 3.5 (x64) 'package': [2] Error: Installation failed for component Microsoft .NET Framework 3.5 (x64) 'package'. MSI returned error code 1603 [09/07/09,19:39:45] WapUI: [2] DepCheck indicates Microsoft .NET Framework 3.5 (x64) 'package' is not installed. [10/17/09,12:04:21] Microsoft .NET Framework 3.5 (x64) 'package': [2] Error: Installation failed for component Microsoft .NET Framework 3.5 (x64) 'package'. MSI returned error code 1603 [10/17/09,12:04:37] WapUI: [2] DepCheck indicates Microsoft .NET Framework 3.5 (x64) 'package' is not installed. [10/17/09,13:04:23] Microsoft .NET Framework 3.5 (x64) 'package': [2] Error: Installation failed for component Microsoft .NET Framework 3.5 (x64) 'package'. MSI returned error code 1603 [10/17/09,13:05:05] WapUI: [2] DepCheck indicates Microsoft .NET Framework 3.5 (x64) 'package' is not installed. [10/17/09,13:29:08] Microsoft .NET Framework 3.5 (x64) 'package': [2] Error: Installation failed for component Microsoft .NET Framework 3.5 (x64) 'package'. MSI returned error code 1603 [10/17/09,13:29:25] WapUI: [2] DepCheck indicates Microsoft .NET Framework 3.5 (x64) 'package' is not installed. Question is, are there other temp files or logs that require deletion? Am I required to install previous versions of .NET and support packages to get this one to work? I have this exact issue on a Vista 32 bit system as well. Thank you for adding clarification to this topic as it seems to be a fairly common and persistent issue. -Dave

A microsoft tech has been working on my .net framework failure to install since last Thursday and he gave me the exact same instructions and it all failed to work. It's now Saturday Oct. 17 and the tech still has not been able to resolve my problem. Might as well accept the fact that Microsoft does not know how to fix this problem and apparently won't know anything new until next week or Monday at the earliest. After this many years of having Windows Update you'd think they would already have all the bugs worked out.

Hello to all, I would advise trying the following: Download the .NET Framework Cleanup Utility from this location: http://blogs.msdn.com/astebner/attachment/8904493.ashx Run the utility, cleaning off EVERY version of .NET Framework Restart the computer after the cleanup process has completed Download the stand-alone .NET Framework 3.5 package from here: http://www.microsoft.com/downloads/details.aspx?FamilyId=333325FD-AE52-4E35-B531-508D977D32A6&displaylang=en Note: Microsoft .NET Framework 3.5 contains many new features building incrementally upon .NET Framework 2.0 and 3.0, and includes .NET Framework 2.0 service pack 1 and .NET Framework 3.0 service pack 1 After the download, install the package and then restart your computer Let us know what happens, Thanks! Ryan Thieman Microsoft Answers Support Engineer Visit our Microsoft Answers Feedback Forum and let us know what you think.

Error Code: 643 (Can't install KB951847)

Answer accepted by question author

Anonymous

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:

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

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

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

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

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.

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

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

When the error appears, please press the "Print Screen" key (PrtScn) on your keyboard.
Click "Start", click "Run", type MSPAINT, and click "OK".
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".
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

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Error Code: 643 (Can't install KB951847)

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