A short post based on a gotcha experience in yet another busy work day - unable to logon to AX after restoring the Contoso demo database for AX 2012 R2? Check if your user account (typically userid admin) is connected to a Data Partition (like 'initial'). And make sure you know the new parameters in the Client Configuration Utility or -Partition= command line parameter. The message returned from AX is less than self explaining (unable to create user session...). Procedure described on Partnersource (maybe also available from Customersource)..
Still a lot to learn for everyone I think.
And another nice feature added to AX 2012.