RMAN-06138

Error: RMAN-06138: controlfile not mounted - must specify AT clause with REPORT command

Causa: A REPORT SCHEMA with no at_clause was issued, and there is no recovery catalog, and there is also no control file mounted at the target database, so there is no place to get the information about the current list of files comprising the database.

Acción: Use a recovery catalog or mount a control file at the target database.