10.7 User not appearing after Startup?

Hi, I've got the following problem:
I have a MBA, OS 10.7.3 with one Admin user.
Then I copied another user with the migration assistant.
Switching between users and everything else no problem.
But: When I reboot, only the Adminuser shows up, not the newly migrated one.
I already tried to make the new user an admin.
I already deleted the com.apple.loginwindow.plist - still the same.
Anybody an idea to get the second account to show up at startup?
Harry

 

Ok, I went to the Geniusbar:
The problem was, the computer had Filevault activated when I migrated the new user on to it.
So switching Filevault off and on again solved the problem.
They said it's a feature not a bug: Only a user who agreed on Filevault could unlock the mac after startup.