I am running Vista and have SSO working. I was told when I set up the server that I needed to have all of the Windows Logon options. I am not sure that I do need them all checked but with that set up like I said before SSO does work with Vista.
Might not be too much of a help but it's something
Ok I have them all check Attempt automatic Windows logon Require re-logon to Endpoint Encryption Automatically Logon as pre-boot user Endpoint Encryption logon component always active Set Endpoint Encryption password to Windows password Must match Windows user name
I did not check Require logon to Endpoint Encryption (which will make another logonscreen)
Actually, I believe the option you left off is for when a user logs off. That way the next user login gets picked up by MEE. They should only get the one login, if their Windows password is still the same as stored in the SSO credentials.
The wording is different between your version and mine but I believe the option you didn't select is the one you must have to enable SSO with Vista and higher. In 5.1.3 it's "Require SafeBoot logon". With Win7 I left out "Require SafeBoot re-logon" and SafeBoot logon component always active" and SSO works well. Everything else in the Windows Logon is checked.