My account is hidden from start login screen after migrating it to a new Macbook
From OS X: About FileVault 2:


  Users not enabled for FileVault unlock will only be able to log in to that Mac after an unlock-enabled user has started or unlocked the drive. Once unlocked, the drive remains unlocked and available to all users, until the computer is shut down.


In order to enable the migrated user for FileVault:


Log in with the account which works
Run Preferences, go to "Security &amp; Privacy" and then the "FileVault" tab
Check for any user accounts which are not enabled yet and log them in (once)