SAML SSO Using Logged In Windows Credentials

Thank you everyone for your help. We now have IdP initiated working. The basic configuration was there, I needed to remove the SSO Credential Mapping and I also had the incorrect SSO Configuration associated with the Access Policy. However the SP initiated is not working correctly. When accessing the SP initiated URL in Internet Explorer, the client is redirected to the IdP and is then prompted for Windows security credentials. The 401 Response appears to be working because the logs show the varible is set Session variable 'session.logon.last.username' set to 'username@domain.com'. If the client cancels the Windows credentials prompt, they are prompted by a Windows download dialog asking if they want to Open or save sso from idp.domain.com. If they then reenter the SP URL in the browser again, they get successful access to the site using SAML SSO.

If they try to access the site in Chrome they get the following The webpage at https://idp.domain.com/saml/idp/profile/redirectorpost/sso might be temporarily down or it may have moved permanently to a new web address. Again, the logs show the username variable being set and successful sent through Access Policy. It seems there is some issue accessing the saml/idp/profile/redirectorpost/sso site.

Would there be any issues using Kerberos with SP initiated access?