Register ASP.NET with IIS Application Pool

Product: CMS

Version: CMS 8, 8.x

Published: February 24, 2014

Last updated: 1/30/2021



In some instances, an issue will occur during an upgrade or install of CMS 8.0, causing the CMS installer to not register ASP.NET 4.0 with the  Dynamic Site Server Preview (DSSPreview) application pool. Symptoms, beyond installer error, will include a 404 error when trying to preview a page within CMS. This article explains how to register ASP.NET with IIS, manually.


This article explains how to manually register ASP.NET 4.0 with IIS.

When multiple version of the .NET framework are installed on a single computer, the version of the Common Runtime Language used is determined by ISAPI mapping. Microsoft has created the ASP.NET IIS Registration Tool to allow for manual configuration of script maps.


Administrator access to the server where CMS is installed.


I. Determine the version of ASP.NET that is running:

  1. Navigate to c:\Windows\Microsoft.NET\Framework.
  2. Find the directory for ASP.NET 4.0. Directories will be properly named with a version number such as "v.4.0.30319" (the current version as of this writing).

II. Register ASP.NET with IIS:

  1. Open up the Windows Command Line (Start->Run cmd.exe).
  2. Navigate to the directory determined by Step I.2.
  3. Run the following command:  aspnet_regiis.exe -ir

You may need to recycle the DSSPreview Application Pool for changes to take affect.

Additional Information

This change will affect all IIS sites on the server. Some planning and caution is required before making this change.


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