Fast User Switching Not Working (Immediately Signs Off)

Hi,

Whenever I try to 'Switch User' on my Windows 7 computer it start to log in, however immediately after succeeding it signs off, returns to the login screen.

Some debugging showed that disabling the SGNAuthService solves the problem. So I was wondering what the SGNAuthService exactly does, and whether there is another solution to get the user switching to work.

Thanks,

Jelmer Hoogendoorn