Oracle Error Message
ORA-19616: output file name must be specified if database not mounted
Reason for the Error
A datafile restore specified no target file name, but the database is not mounted. The database must be mounted when no target file name is specified, so that the target file name can be obtained from the control file.
Solution
The restore conversation remains active. If you wish to restore datafiles without their target file names, then mount the database before continuing. Otherwise, a target file name must be specified on all datafile restoration calls.