How to correct UNNAMED{nnnnn} datafile problem

When standby_file_management is auto and file path which is added to the primary database does not exist on standby site, then standby database creates a dummy datafile such as

{path}/UNNAMEDnnnnn

To correct this problem, you should set standby_file_management to manual and create standby datafile :

alter system set standby_file_management=manual;
alter database create datafile '{path}/UNNAMEDnnnnn' as '{standby file path}/{data file name}.dbf' size xxxM;