Asp.net 4.0 has not been registered

When I try to open my Visual Studio project I get the following error:

>Asp.Net has not been registered on the webserver you need to manually configure your webserver for Asp.net 4.0.

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Update:
Nevermind I fixed it:

I just repaired .Net Framework 4.0 and the issue was resolved.

I also fixed this issue by running

aspnet_regiis -i

using the visual studio command line tools as an administrator

This solved the problem

C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis -i

Be sure to run the command prompt as administrator

For those getting this error in after installing .NET Framework 4.6 - Read and install one of these hotfixes to resolve the issue.

To resolve 'ASP.NET 4.0 has not been registered. You need to manually configure your Web server for ASP.NET 4.0 in order for your site to run correctly' error when opening a solution we can:

1 Ensure the IIS feature is turned on with ASP.NET. Go to Control Panel\All Control Panel Items\Programs and Features then click 'Turn Windows Featrues on. Then in the IIS --> WWW servers --> App Dev Features ensure that ASP.NET is checked.

2 And run the following cmd line to install

C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis -i

Hope this helps

The aspnet_regiis approach described above doesn't appear to work on Windows 8.1:

C:\Windows\system32>aspnet_regiis -i

> Microsoft (R) ASP.NET RegIIS version 4.0.30319.33440
Administration utility to install and uninstall ASP.NET on the local machine.
Copyright (C) Microsoft Corporation. All rights reserved.
Start installing ASP.NET (4.0.30319.33440).
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 http://go.microsoft.com/fwlink/?LinkID=216771.
Finished installing ASP.NET (4.0.30319.33440).

As indicated in the message, I went to:

1. Start
2. Turn Windows features on or off
3. .NET Framework 4.5 Advanced Services

and checked ASP.NET 4.5.

This seems to have resolved the problem.

Open:

Start Menu
-> Programs
-> Microsoft Visual Studio 2010
-> Visual Studio Tools
-> Visual Studio Command Prompt (2010)

Run in command prompt:

aspnet_regiis -i

Make sure it is run at administrator, check that the title starts with Administrator:

http://msdn.microsoft.com/en-us/library/k6h9cz8h.aspx - See this on registering IIS for ASP.NET 4.0

Asp.net 4.0 has not been registered

Visual Studio 2013 Download Visual Studio 2013 Update 4 For more information on the Visual Studio 2013 Update 4, please refer to: Visual Studio 2013 Update 4 KB Article

Visual Studio 2012 An update to address this issue for Microsoft Visual Studio 2012 has been published: KB3002339 To install this update directly from the Microsoft Download Center, here

Visual Studio 2010 SP1 An update to address this issue for Microsoft Visual Studio 2010 SP1 has been published: KB3002340 This update is available from Windows Update To install this update directly from the Microsoft Download Center, here http://download.microsoft.com/download/6/7/E/67E041A1-00DA-4948-90BE-75A0146C08F5/VS10SP1-KB3002340-x86.exe

Go to Visual Studio 2010 Command prompt and set the Directives as :

C:\Windows\Microsoft.NET\Framework\v4.0.30319>

then install IIS by following command:

C:\Windows\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis -i

now iis will working.. its better if your restart the computer

I had the same issue but solved it...... Microsoft has a fix for something close to this that actually worked to solve this issue. you can visit this page <http://blogs.msdn.com/b/webdev/archive/2014/11/11/dialog-box-may-be-displayed-to-users-when-opening-projects-in-microsoft-visual-studio-after-installation-of-microsoft-net-framework-4-6.aspx>

The issue occurs after you installed framework 4.5 and/or framework 4.6. The Visual Studio 2012 Update 5 doesn't fix the issue, I tried that first.

The msdn blog has this to say: "After the installation of the Microsoft .NET Framework 4.6, users may experience the following dialog box displayed in Microsoft Visual Studio when either creating new Web Site or Windows Azure project or when opening existing projects....."

According to the Blog the dialog is benign. just click OK, nothing is effected by the dialog... The comments in the blog suggests that VS 2015 has the same problem, maybe even worse.

If ASP.NET 4.0 is not registered with IIS

Use this step if u cant access using run command

Go to

C Drive
-->>windows
-->>Microsoft.Net
-->>Framework
-->>v4.0.30319

(Choose whatever framework to register with IIS me selecting Framework 4)

-->>aspnet_regiis

(Double-click or right click & choose run as administrator)

I had this problem on Windows 8.1 which wouldn't support the aspnet_regiis -i approach.

Instead you need to go to Control Panel, locate the "Turn Windows features on or off" option and drill down as follows:

Internet Information Services -> World Wide Web Services -> Application Development Features and check the "ASP.NET 4.5" option. In checking this box, other options such as ".NET Extensibility 4.5" and the ISAPI options will be checked automatically.

Apply the changes by clicking OK. Restart your website in IIS and your site should now be accessible.

I repaired it using the Microsoft .NET Framework Repair Tool. After reloading my project a couple of times after that the problem went away.