I have installed IIS and .NET 4.0 on Windows Server 2003.

I have a web ready website that that targets .NET 4.0 and have updated the default website home directory to map to the website's directory.

When I visit the website in a web browser (localhost, localhost:80), I get a 404 error (File or directory not found).

Here is the IP address so you can see for yourself.

How do I get my ASP.NET 4.0 website to run?


You need to install IIS before installing .NET 4.0. If IIS is installed after .NET 4.0, you need to use command prompt and run the aspnet_regiis tool located in the .net 4.0 directory.

  1. Did you install ASP.NET in the using the Add or Remove Programs dialog box on the Control Panel?
  2. In IIS Manager: did you allow the ASP.NET Web Service Extension?

See this Technet article about Installing ASP.NET (IIS 6.0).

  • 2
    I had to allow the ASP.NET Web Service Extension. Thanks! – Paul Knopf Dec 31 '10 at 17:32
  • This wasn't exactly what was wrong with my installation, but it pointed me in the right direction. I had to allow ASP.NET in Web Service Extensions (Start > IIS Manager > [server](local computer) > Web Service Extensions > ASP.NET(2 or 4) > Allow. Thanks for the link! – delliottg Jul 18 '14 at 14:54

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