This code appears to resolve the issue, when added to Application_Start() in Global.asax: PropertyInfo p = typeof(System.Web.HttpRuntime).GetProperty(“FileChangesMonitor”, BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static); object o = p.GetValue(null, null); FieldInfo f = o.GetType().GetField(“_dirMonSubdirs”, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.IgnoreCase); object monitor = f.GetValue(o); MethodInfo m = monitor.GetType().GetMethod(“StopMonitoring”, BindingFlags.Instance | BindingFlags.NonPublic); m.Invoke(monitor, new object[] { }); http://dotnetslackers.com/Community/blogs/haissam/archive/2008/11/12/disable-session-expiration-when-using-directory-delete.aspx With these … Read more