I have the same error ... we must add manually wuweb to activex list of Internet Explorer Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Code Store Database\Distribution Units\{6414512B-B978-451D-A0D8-FCFDF33E833C}] "SystemComponent"=dword:00000000 "Installer"="MSICD" [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Code Store Database\Distribution Units\{6414512B-B978-451D-A0D8-FCFDF33E833C}\Contains] [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Code Store Database\Distribution Units\{6414512B-B978-451D-A0D8-FCFDF33E833C}\Contains\Files] "C:\\WINDOWS\\system32\\wuweb.dll"="" [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Code Store Database\Distribution Units\{6414512B-B978-451D-A0D8-FCFDF33E833C}\DownloadInformation] "CODEBASE"="http://v5.windowsupdate.microsoft.com/v5consumer/V5Controls/en/x86/client/wuweb_site.cab?1118238907375" "INF"="C:\\WINDOWS\\Downloaded Program Files\\wuweb.inf" [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Code Store Database\Distribution Units\{6414512B-B978-451D-A0D8-FCFDF33E833C}\InstalledVersion] @="5,4,3790,2182" "LastModified"="Tue, 03 Aug 2004 22:48:02 GMT" EDIT: After testing and testing and testing ... I choose the silent install in RunOnceEx with all hotfixes ... It's more clean and it's easy to maintain ...