Unable to start program 'http://localhost/Default.aspx'. VS2010

Question

I cannot start my website from Visual Studio 2010 anymore.

For a few days I cannot start my project in a web browser using F5. When I open my web application directly by

Answer 1

I just ran into this problem in Visual Studio 2013. I had to enable Anonymous Authentication.

Click on the project node in solution explorer. Hit F4 to show the properties window. Change the Anonymous Authentication option to Enabled.