This problem started for me beginning of 2009. Microsoft updates randomly failing. If I disable Antivirus and antispyware protection, updates do not fail. This happens with my 170 PCs running Windows XP SP3, and servers running Windows 2003 and 2008 32/ 64-bits. I search the Forum but couldn't find a post regarding this problem. I am sure I am not the only one with this problem. Can you please tell me if this was discussed before and give me a link for the post or tell me how to avoid these failures? I attach my configuration. Username changed and password deleted... Thanks in advance.