I have added a new web site on an existing Windows Server 2012 IIS installation. The installation already had ASP.NET configured on the existing sites.

What is the right way to enable ASP.NET on the new web site? All the documentation I've found talks about using Server Manager to add the role/feature, but that's already there so that's not helpful.

On previous versions I would use aspnet_regiis -i but that doesn't work on Server 2012:

C:\Windows\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis -i
Microsoft (R) ASP.NET RegIIS version 4.0.30319.17929
Administration utility to install and uninstall ASP.NET on the local machine.
Copyright (C) Microsoft Corporation.  All rights reserved.
Start installing ASP.NET (4.0.30319.17929).
This option is not supported on this version of the operating system.  Administr
ators should instead install/uninstall ASP.NET 4.5 with IIS8 using the "Turn Win
dows Features On/Off" dialog,  the Server Manager management tool, or the dism.e
xe command line tool.  For more details please see http://go.microsoft.com/fwlin
Finished installing ASP.NET (4.0.30319.17929).

What is the correct procedure?

Edit: Here's a screenshot proving the role is correctly configured.

The machine is running ASP.NET applications correctly on another web site so I know the role is 100% installed correctly.

  1. Open IIS Manager
  2. Expand the server name node
  3. Select 'Sites'
  4. On the 'Actions' section push 'Add Website...'
  5. Set the 'Site name', 'Physical path', and the 'Binding' and push 'OK'. Notice that the DefaultAppPool in IIS8 is for Asp.Net4

The next step do the trick for IIS8:

  1. Expand 'Default Web Site'. Your site name should be under.

  2. Right click on you site name, and push 'Convert to Application'

That's it. Now it should work.

It took me three hours to find that right click -> convert to application thing... I hope this answer will save others time.


Ultimately, I removed the already installed ASP.NET 3.5 and 4.5 features, then put them back (I had to put back WCF HTTP Activation as well for each). That got the new web site working and seems to have kept the other existing ASP.NET sites and applications working, although I won't know for sure without more testing.

This was obviously a very stupid solution because it ran the risk of breaking the existing ASP.NET applications on the server, and certainly meant a downtime on those applications during this process for no good reason. But it did work.


You need to select ASP.NET 4.5 in features on the second step while installing IIS on your server. You have to select all features while installing IIS on the server. You can reveiew IIS Installation URL to know more.

  • I already have that role installed, as I said. The machine already has ASP.NET installed correctly on other sites. – MikeBaz - MSFT Apr 10 '13 at 18:06
  • Can you take screenshot of roles and feature and share with us? Specially in IIS feature – maniargaurav Apr 12 '13 at 12:24

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