To remove OWA from SSO follow these steps
- Replace C2WTShost.exe.config located here C:\Program Files\Windows Identity Foundation\v3.5\ with the original file.
- Replace the OWA web.config located here C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\ with the original file.
- Replace the ECP web.config located here C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\ecp\Web.config with the original file.
- Open the Exchange Management Console.
- Under Server Configuration -> Client Access, open the owa configuration under the “Outlook Web App” tab.
- In the Authentication tab and make sure “Use forms-based authentication” is checked.
- Open up Internet Information Services (IIS) Manager.
- Expand the site where OWA is installed and click on the “owa” application.
- Double-click the Authentication icon and verify that Anonymous Authentication is set to Disabled.