After installing updates this past night our webservers began exhibiting odd behaviour. All our Windows Communication Foundation (WCF) services began returning 405 Method Not Allowed. I’m not sure which patch was responsible for causing this, but I strongly dislike it when applying updates change my configuration. When I tried to access the svc file directly from a browser I got a 404. This led me to check the .svc mapping. Don’t ask me why, but as it turns out this mapping had been removed. Adding it back solved the problem. I haven’t tracked it down, and I don’t think I will, but the culprit is most likely part of either Microsoft .NET Framework 2.0 Service Pack 1 (KB110806) or Microsoft .NET Framework 3.0 Service Pack 1 (KB929300). The other updates installed can almost certainly be disregarded.