When I create new VS2008 asp.net application it builds fine. But when I start debugging I get below error in browser. I've rebuilt the app. The Inherits clause of the markup page matches the class in the code-behind C#. Any clues? Server Error in '/' Application. Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: Could not load type 'WebApplication3._Default'. Source Error: Line 1: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebApplication3._Default" % Line 2: Line 3: Source File: /Default.aspx Line: 1 Version Information: Microsoft .NET Framework Version:2.0.50727.4952; ASP.NET Version:2.0.50727.4927