KB2468871 System Update Install Error! (error 643)

original title: KB2468871 System Update Install Error!

Ok Now I have tried to install from windows update and manually trying to install this update  KB2468871

It is not working and it keeps giving me an error

Error code 643. 
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:


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


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:


Install the KB2468871 update you downloaded earlier.

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Question Info

Last updated April 29, 2021 Views 33,624 Applies to: