Microsoft Project Server 2010 databases in backward compatibility mode (BCM) cannot be upgraded to Project Server 2013 . ...

Microsoft Project Server 2010 databases in backward compatibility mode (BCM) cannot be upgraded to Project Server 2013 . Before upgrading to Project Server 2013  please disable BCM on your Microsoft Project Server 2010 PWA instance (http://technet.microsoft.com/en-us/library/gg502585)