Permission error when executing a 5.6 GB sqlcmd file
@Mihai, As  Daniel Hutmacher already said,Express Edition is limited in database size. As per sqlmag BOL http://sqlmag.com/sql-server-2012/sql-server-2012-express-editions, if you are using SQL Server Express with Advanced Services. It is limited to 4GB and can access only the local instance.

Even in dba.stackexchange the Shanky How many users are supported on SQL Server 2012 Express? has also explain the limitation of SQL Server Express edition .