IIS 404.3 Error After Installing Retain

  • 7021403
  • 14-Sep-2017
  • 14-Sep-2017


Retain Unified Archiving 4.x+
Windows 7, 2008, 2012 , 2016 Server


Issue:  After the installation of Retain, the client attempts to access the Retain web-interface to complete the setup, but the page cannot be reached. The web-page displays the following error:  

HTTP Error 404.3-Not Found
The page you are requesting cannot be served because of the extension configuration. If the page is script, add a handler. If the file should be downloaded, add a MIME map. 

Even after the ISAPI Extensions and ISAPI Filters are installed, the error still occurs. 

How do you resolve this error and allow access to the Retain Server interface?


The solution is to ensure that the ISAPI Extensions and ISAPI Filters are installed so that the Retain software can properly connect to the web server, and display the interface. It is highly recommended that IIS, along with the ISAPI Extensions and ISAPI Filters, are installed prior to the installation of Retain.

If Retain is installed prior to IIS, or the ISAPI Extensions and ISAPI Filters , then the Retain software will  need to be completely uninstalled and reinstalled so that it can establish a proper connection to the IIS web server.  To reinstall Retain, follow these steps: 
  1. Stop the Retain-Tomcat7(8) service from services.msc
  2. Go into the Environment Variables on the Windows machine that is being used. In the System variables section, remove all RETAIN variables:
            2. RETAIN_HOME
            3. RETAIN_JAVA_HOME
            4. RETAIN_JAVA_VERSION
            5. RETAIN_JRE_HOME
  3. Remove, or rename, the Retain directory. 
  4. Proceed with the initial installation of Retain
Once Retain is installed with the ISAPI Extensions and ISAPI Filters in place the web page will be displayed.


IIS and the ISAPI Extensions and ISAPI filters are not installed prior to installing the Retain software. 

Additional Information

This information comes after the completed install of Retain steps, which leads to the confusion above; as client believes either ISAPI is done after installation or was not required to begin with.

Performing the ISAPI install after the installation yields failure as the installer must be run while ISAPI exists.