I am getting the following error with windows update and cannot get the update to install. Security Update for Microsoft .NET Framework, Version 1.1 Service Pack 1 (KB886903) Installation date: 10/11/2007 3:10 AM Installation status: Failed Error details: Code 643

This KB may be able to help with your issue: http://support.microsoft.com/kb/923100/

I had the same problem. This was being caused by Bitdefender (My antivisrus software) stopping the update of the registry. When I tried again BitDefender gave me the option of allowing the update - this option was selected and the update applied successfully.

Ok, I have just managed tofix this error after many attempts. Here it is. First, I downloaded "windows install cleanup" tool. next goto "add remove programs" and manually remove .NET Framework, Version 1.1 Service Pack 1 If like me it appears not to work you need to run the Cleanup tool you just downloaded and remove the service pack. After this you need to manually download and Install the service pack direct from the microsoft website, use the following url http://www.microsoft.com/downloads/details.aspx?familyid=A8F5654F-088E-40B2-BBDB-A83353618B38&displaylang=en. After you have installed this you will need to restart your pc and then goto windows update and run it. Hope this works for you, it worked for me and I was really getting fed up with this error, I cant believe Microsoft have not put out a patch for this problem. Good hunting

thanks Paulit works. one thing to add.before installing the .net framework 1.1 service pack 1. you might want to install the .net framework 1.1 package first. or there is an error coming out when you try to install the service pack 1.

ola eu estava com mesmo problema eu retirei net framework 1.1 baixei atualizaçao e depois baixei o net framework 1.1 deu certo

It hasn't worked for me. I went through the first stage and downloaded the windows install cleanup" tool and removed .NET Framework, Version 1.1 Service Pack 1(at least I think I did). But when I tried to install the .net framework 1.1 package it failed. I went on and installed the service pack and that seemed to work. But after restarting my pc it still won't load several of the updates and I get the same failure code.

Hi, The Windows update error code 643 in Windows 7 Operating System could be resolved by the two methods. The first one is to fix the MSI software update registration corruption issues. For this you have to first confirm whether the product is affected or not. Then you have to re-create software update cache registry details and should delete the remaining software update references. If the problem is not solved then, you are advised to repair the .NET Framework using the .NET Framework Cleanup Tool. Get more information to fix windows update error 643 : http://supportformicrosoft.iyogi.com/windows-7/windows-7-error-code-643.html Hope this information helps you.

I had the same problem. This was being caused by Bitdefender (My antivisrus software) stopping the update of the registry. When I tried again BitDefender gave me the option of allowing the update - this option was selected and the update applied successfully. Hi, I also had this problem being caused by bullguard which I heard once used bitdefenders av engine. dont know how true this is but disabling bullguard fixed the problem, im going to reinstall it anyway 'cos disabling the av everytime i want 2 update isnt ideal