It currently defines this abstract method: protected abstract void Convert(TextWriter writer, LoggingEvent loggingEvent, HttpContext httpContext)
I would recommend changing it to: protected abstract void Convert(TextWriter writer, LoggingEvent loggingEvent, HttpContext*Base* httpContext) Effectively, HttpContext.Current is not very useful anymore in more recent versions of ASP.NET. As they are promoting an asynchronous programming model where operations complete on completion threads. And they also encourage the use of the ParallelTaskLibrary for queuing work items. The bulk of your operations are going to execute on these threads, and on these threads, HttpContext.Current is null. HttpContextBase is what's being used now and it's easy to convert HttpContext.Current to an HttpContextBase like this: new HttpContextWrapper(HttpContext.Current) Here's some more info on the matter. http://www.splinter.com.au/httpcontext-vs-httpcontextbase-vs-httpcontext/
