How to install ASP.NET 4.5 on Windows 8 and Windows Server 2012

Applies to: ASP.NET 4.5Windows 8


In previous versions of Microsoft Windows running Internet Information Services (IIS), the aspnet_regiis -I command could be used to install the ASP.NET feature. Starting in Windows 8, the following problems may occur when trying to install ASP.NET using aspnet_regiis:

  1. If you run aspnet_regiis -I to install ASP.NET 4.5 on IIS8, an error message similar to the following will be displayed:

    This option is not supported on this version of the operating system. Administrators should instead install/uninstall ASP.NET 4.5 with IIS8 using the "Turn Windows Features On/Off" dialog, the Server Manager management tool, or the dism.exe command line tool. For more details please see

  2. If you have an application that uses setup projects to install an application on IIS, the installation will fail to enable ASP.NET 4.5 and the application may fail to install.
  3. If you install an application on Windows 8 that attempts to install ASP.NET 4.5 using aspnet_regiis -I, the application will fail to enable ASP.NET 4.5.


The Aspnet_regiis.exe utility is no longer used for installing and uninstalling ASP.NET 4.5 on Windows 8. ASP.NET 4.5 is now a Windows component and can be installed and uninstalled just like any other Windows component.


To install or uninstall ASP.NET 4.5 on Windows 8 or Windows Server 2012, use one of the following options:
  • Run the following command from an administrative command prompt: dism /online /enable-feature /featurename:IIS-ASPNET45
  • For Windows 8 client computers, turn on "IIS-ASPNET45" in "Turn Windows Features On/Off" under "Internet Information Services-> World Wide Web Services -> Application Development Features -> ASP.NET 4.5".
  • For Windows Server 2012 computers, enable "IIS-ASPNET45" using Server Manager, under "Web Server (IIS) -> Web Server ->Application Development -> ASP.NET 4.5".