KB2468871 System Update Install Error! (error 643)

If you followed the useless MS solution of http://support.microsoft.com/kb/2431208 and restarted the computer after installing .NET and prior to doing the updates, or any of the other “fixes” but are still getting the same problem as I was, then try this fix which worked when all else had failed. [I was getting repeat installs of the same update initially but after a few fixes, I was getting a failed update.]

.NET Update Fix

Uninstall all of the .NET Security updates with Revo Uninstaller in Advanced mode, deleting any leftover files/registry items. Then go to Programs & Features and uninstall .NET Framework, and then .NET Client. Once done download the .NET Cleanup_tool and run it in the ".NET4" cleanup mode and then run it again in the "Win7 all versions" mode. Go into Programs & Features> "Turn Windows features on or off" > Make sure the "Microsoft .NET Framework 3.5.1" and ".NET Environment" under "Windows Process Activation Service" are unchecked. Redo the Cleanup-tool in the same way and then download and install the Full .NET Framework package. Create a System Restore point (in case the update process does not work and you can come back to this point without having to go through the prior process again). Without rebooting check Windows Update and install all of the updates published prior to 9/11 and when done do all the rest (but not the optional ones). Now reboot and go to Windows Features again and recheck ".NET Environment" under "Windows Process Activation Service" if it had been previously checked (same for the other one). Now you can do any optional updates if desired.

Revo Uninstaller: http://www.revouninstaller.com/start_freeware_download.html

.NET Cleanup_Tool: http://blogs.msdn.com/b/astebner/archive/2008/08/28/8904493.aspx

.NET Standalone installer: http://msdn.microsoft.com/en-us/library/5a4x27ek.aspx

Now tell us why you installed .NET Framework 4 (Client Profile?) in the first place?

Finally after weeks of frustration I was able to fix this mess, none of the advice microsoft provided worked, uninstalling reinstalling, using microsoft .net removal tool, microsoft fixit, disabling UAC, and numerous other things which did nothing at all.

The source of this problem with KB2468871 is that a .dll needed for it to install is not present for whatever reason, copying and inserting the .dll where it needs to be will allow you to install this update.

Download the KB2468871 update here:

http://www.microsoft.com/download/en/details.aspx?id=3556

Try to install it, so that it extracts the needed .dll

C:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.Xml.Serialization\v4.0_4.0.0.0__b77a5c561934e089

Go to there and you should see the .dll file "System.Xml.Serialization.dll" If you can't find it do a search for it.

Copy it.

Paste it here C:\Windows\Microsoft.NET\Framework\v4.0.30319

And paste it here:

C:\Windows\Microsoft.NET\Framework64\v4.0.30319

Install the KB2468871 update you downloaded earlier.

Thank you thank you thank you!!! Absolute LEGEND! This fixed the problem first time round, update installed without a hitch! :D

No, I jam.