https://www.dotnetzone.gr:443/cs/blogs/birbilis/archive/2010/01/21/fix-error-code-80240016-when-installing-windows-defender-definition-update.aspxWhen running the free online Windows Live OneCare antivirus/maintenance scanner (available as an ActiveX control hosted in a webpage - for Internet Explorer only), you may notice that Windows Update can't install Windows Defender definition updates, sayingelCommunityServer 2.1 SP3 (Build: 20423.1)