From 2.5 RlsNotes :: Data Definition Language :: Evolution of CREATE DATABASE :: The DIFFERENCES FILE Argument for CREATE DATABASE:
SQL> alter database drop difference file;
SQL> alter database begin backup;
Statement failed, SQLCODE = -607
unsuccessful metadata update
-STORE RDB$FILES failed
-message length error (encountered 278, expected 276)
It is not a user friendly message but it means we have no difference file. Perhaps curiously,
the engine does not rescue the situation and create the delta using the default mechanism.
In fact, this has been fixed by Claudio himself for 2.5 RC3 and 3.0 Alpha 1 (see
I've also tested it in practice and it works correctly.